Pub Date : 2024-08-28DOI: 10.1103/physrevmaterials.8.084204
Eduárd Zsurka, Cheng Wang, Julian Legendre, Daniele Di Miceli, Llorenç Serra, Detlev Grützmacher, Thomas L. Schmidt, Philipp Rüßmann, Kristof Moors
We develop an accurate nanoelectronic modeling approach for realistic three-dimensional topological insulator nanostructures and investigate their low-energy surface-state spectrum. Starting from the commonly considered four-band bulk model Hamiltonian for the family of topological insulators, we derive new parameter sets for and . We consider a fitting strategy applied to ab initio band structures around the point that ensures a quantitatively accurate description of the low-energy bulk and surface states while avoiding the appearance of unphysical low-energy states at higher momenta, something that is not guaranteed by the commonly considered perturbative approach. We analyze the effects that arise in the low-energy spectrum of topological surface states due to band anisotropy and electron-hole asymmetry, yielding Dirac surface states that naturally localize on different side facets. In the thin-film limit, when surface states hybridize through the bulk, we resort to a thin-film model and derive thickness-dependent model parameters from ab initio calculations that show good agreement with experimentally resolved band structures, unlike the bulk model that neglects relevant many-body effects in this regime. Our versatile modeling approach offers a reliable starting point for accurate simulations of realistic topological material-based nanoelectronic devices.
我们为现实的三维拓扑绝缘体纳米结构开发了一种精确的纳米电子建模方法，并研究了它们的低能表面态谱。从通常认为的 Bi2Se3 系列拓扑绝缘体的四带 k-p 体模型哈密顿开始，我们得出了 Bi2Se3、Bi2Te3 和 Sb2Te3 的新参数集。我们考虑将拟合策略应用于 Γ 点附近的 ab initio 带状结构，以确保定量准确地描述低能体态和表面态，同时避免在较高的时刻出现非物理的低能态，而这是通常认为的微扰方法所无法保证的。我们分析了拓扑表面态的低能谱中由于能带各向异性和电子-空穴不对称而产生的效应，这些效应产生的狄拉克表面态自然地局域在不同的侧刻面上。在薄膜极限，当表面态通过体层发生杂化时，我们采用薄膜模型，并通过原子序数计算推导出厚度相关的模型参数，这些参数与实验解析的能带结构显示出良好的一致性，而不像体层模型在这一机制中忽略了相关的多体效应。我们的多功能建模方法为精确模拟基于拓扑材料的现实纳米电子器件提供了一个可靠的起点。
{"title":"Low-energy modeling of three-dimensional topological insulator nanostructures","authors":"Eduárd Zsurka, Cheng Wang, Julian Legendre, Daniele Di Miceli, Llorenç Serra, Detlev Grützmacher, Thomas L. Schmidt, Philipp Rüßmann, Kristof Moors","doi":"10.1103/physrevmaterials.8.084204","DOIUrl":"https://doi.org/10.1103/physrevmaterials.8.084204","url":null,"abstract":"We develop an accurate nanoelectronic modeling approach for realistic three-dimensional topological insulator nanostructures and investigate their low-energy surface-state spectrum. Starting from the commonly considered four-band <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi mathvariant=\"normal\">k</mi><mo>·</mo><mi mathvariant=\"normal\">p</mi></mrow></math> bulk model Hamiltonian for the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>Bi</mi><mn>2</mn></msub><msub><mi>Se</mi><mn>3</mn></msub></mrow></math> family of topological insulators, we derive new parameter sets for <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>Bi</mi><mn>2</mn></msub><msub><mi>Se</mi><mn>3</mn></msub></mrow><mo>,</mo><mo> </mo><mrow><msub><mi>Bi</mi><mn>2</mn></msub><msub><mi>Te</mi><mn>3</mn></msub><mo>,</mo></mrow></math> and <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>Sb</mi><mn>2</mn></msub><msub><mi>Te</mi><mn>3</mn></msub></mrow></math>. We consider a fitting strategy applied to <i>ab initio</i> band structures around the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi mathvariant=\"normal\">Γ</mi></math> point that ensures a quantitatively accurate description of the low-energy bulk and surface states while avoiding the appearance of unphysical low-energy states at higher momenta, something that is not guaranteed by the commonly considered perturbative approach. We analyze the effects that arise in the low-energy spectrum of topological surface states due to band anisotropy and electron-hole asymmetry, yielding Dirac surface states that naturally localize on different side facets. In the thin-film limit, when surface states hybridize through the bulk, we resort to a thin-film model and derive thickness-dependent model parameters from <i>ab initio</i> calculations that show good agreement with experimentally resolved band structures, unlike the bulk model that neglects relevant many-body effects in this regime. Our versatile modeling approach offers a reliable starting point for accurate simulations of realistic topological material-based nanoelectronic devices.","PeriodicalId":20545,"journal":{"name":"Physical Review Materials","volume":"61 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142226375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Recently reported remarkably high radiation tolerance of double-polymorphic structure brings this ultrawide-band-gap semiconductor to the frontiers of power electronics applications that are able to operate in challenging environments. Understanding the mechanism of radiation tolerance is crucial for further material modification and tailoring of the desired properties. In this study, we employ machine-learning-enhanced atomistic simulations to assess the stability of both the gallium () and oxygen () sublattices under various levels of damage. Our study uncovers the remarkable resilience and stability of the -sublattice, attributing this property to the strong tendency of recovery of the defects, especially within the more strongly disordered regions. Interestingly, we observe the opposite behavior of the defects that display enhanced stability in the same regions of increased disorder. Moreover, we observe that highly defective is able to transform into upon annealing due to preserved lattice organization of the sublattice. This result clearly manifests that the ultrahigh stability of the sublattice provides the backbone for the exceptional radiation tolerance of the double-polymorphic structure. These computational insights closely align with experimental observations, opening avenues for further exploration of polymorphism in and potentially in analogous polymorphic families spanning a broad range of diverse materials of complex polymorphic nature.
据最近报道，γ/β-Ga2O3 双多晶结构具有极高的辐射耐受性，这将这种超宽带隙半导体带入了能够在具有挑战性的环境中工作的电力电子应用领域的前沿。了解辐射耐受性的机理对于进一步改性材料和定制所需的性能至关重要。在本研究中，我们采用机器学习增强型原子模拟来评估镓（Ga）和氧（O）子晶格在不同程度的损伤下的稳定性。我们的研究揭示了-亚晶格非凡的恢复力和稳定性，并将这一特性归因于氧缺陷的强烈恢复趋势，尤其是在较强无序区域内。有趣的是，我们观察到 Ga 缺陷的行为恰恰相反，它们在无序度增加的相同区域显示出更强的稳定性。此外，我们还观察到，由于 O 子晶格的晶格组织得以保留，高度缺陷的 β-Ga2O3 能够在退火后转变为 γ-Ga2O3。这一结果清楚地表明，O 亚晶格的超高稳定性为 γ/β 双多晶结构提供了卓越的耐辐射性。这些计算见解与实验观察结果非常吻合，为进一步探索 Ga2O3 的多晶体性质以及潜在的类似多晶体家族开辟了道路，这些家族涵盖了具有复杂多晶体性质的各种材料。
{"title":"Ultrahigh stability of oxygen sublattice in β−Ga2O3","authors":"Ru He, Junlei Zhao, Jesper Byggmästar, Huan He, Flyura Djurabekova","doi":"10.1103/physrevmaterials.8.084601","DOIUrl":"https://doi.org/10.1103/physrevmaterials.8.084601","url":null,"abstract":"Recently reported remarkably high radiation tolerance of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>γ</mi><mo>/</mo><mi>β</mi><mtext>−</mtext><msub><mi>Ga</mi><mn>2</mn></msub><msub><mi mathvariant=\"normal\">O</mi><mn>3</mn></msub></mrow></math> double-polymorphic structure brings this ultrawide-band-gap semiconductor to the frontiers of power electronics applications that are able to operate in challenging environments. Understanding the mechanism of radiation tolerance is crucial for further material modification and tailoring of the desired properties. In this study, we employ machine-learning-enhanced atomistic simulations to assess the stability of both the gallium (<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>Ga</mi></math>) and oxygen (<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi mathvariant=\"normal\">O</mi></math>) sublattices under various levels of damage. Our study uncovers the remarkable resilience and stability of the -sublattice, attributing this property to the strong tendency of recovery of the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi mathvariant=\"normal\">O</mi></math> defects, especially within the more strongly disordered regions. Interestingly, we observe the opposite behavior of the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>Ga</mi></math> defects that display enhanced stability in the same regions of increased disorder. Moreover, we observe that highly defective <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>β</mi><mtext>−</mtext><msub><mi>Ga</mi><mn>2</mn></msub><msub><mi mathvariant=\"normal\">O</mi><mn>3</mn></msub></mrow></math> is able to transform into <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>γ</mi><mtext>−</mtext><msub><mi>Ga</mi><mn>2</mn></msub><msub><mi mathvariant=\"normal\">O</mi><mn>3</mn></msub></mrow></math> upon annealing due to preserved lattice organization of the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi mathvariant=\"normal\">O</mi></math> sublattice. This result clearly manifests that the ultrahigh stability of the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi mathvariant=\"normal\">O</mi></math> sublattice provides the backbone for the exceptional radiation tolerance of the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>γ</mi><mo>/</mo><mi>β</mi></mrow></math> double-polymorphic structure. These computational insights closely align with experimental observations, opening avenues for further exploration of polymorphism in <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>Ga</mi><mn>2</mn></msub><msub><mi mathvariant=\"normal\">O</mi><mn>3</mn></msub></mrow></math> and potentially in analogous polymorphic families spanning a broad range of diverse materials of complex polymorphic nature.","PeriodicalId":20545,"journal":{"name":"Physical Review Materials","volume":"7 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142226376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-28DOI: 10.1103/physrevmaterials.8.084411
A. Castellano, K. Alhada-Lahbabi, J. A. Arregi, V. Uhlíř, B. Perrin, C. Gourdon, D. Fournier, M. J. Verstraete, L. Thevenard
FeRh is well known in its bulk form for a temperature-driven antiferromagnetic (AFM) to ferromagnetic (FM) transition near room temperature. It has aroused renewed interest in its thin-film form, with particular focus on its biaxial AFM magnetic anisotropy which could serve for data encoding, and the possibility to investigate laser-assisted phase transitions, with varying contributions from electrons, phonons, and magnons. In order to estimate the typical temperature increase occurring in these experiments, we performed modulated thermoreflectance microscopy to determine the thermal conductivity of FeRh. As often occurs upon alloying, and despite the good crystallinity of the layer, was found to be lower than the thermal conductivities of its constituting elements. More unexpectedly, given the electrically more conducting nature of the FM phase, it turned out to be three times lower in the FM phase compared to the AFM phase. This trend was confirmed by examining the temporal decay of incoherent phonons generated by a pulsed laser in both phases. To elucidate these results, first- and second-principles simulations were performed to estimate the phonon, magnon, and electron contributions to the thermal conductivity. They were found to be of the same order of magnitude, and to give a quantitative rendering of the experimentally observed . In the FM phase, however, simulations overestimate the low experimental values, implying very different (shorter) electron and magnon lifetimes.
{"title":"Magnetic phase dependency of the thermal conductivity of FeRh from thermoreflectance experiments and numerical simulations","authors":"A. Castellano, K. Alhada-Lahbabi, J. A. Arregi, V. Uhlíř, B. Perrin, C. Gourdon, D. Fournier, M. J. Verstraete, L. Thevenard","doi":"10.1103/physrevmaterials.8.084411","DOIUrl":"https://doi.org/10.1103/physrevmaterials.8.084411","url":null,"abstract":"FeRh is well known in its bulk form for a temperature-driven antiferromagnetic (AFM) to ferromagnetic (FM) transition near room temperature. It has aroused renewed interest in its thin-film form, with particular focus on its biaxial AFM magnetic anisotropy which could serve for data encoding, and the possibility to investigate laser-assisted phase transitions, with varying contributions from electrons, phonons, and magnons. In order to estimate the typical temperature increase occurring in these experiments, we performed modulated thermoreflectance microscopy to determine the thermal conductivity <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>κ</mi></math> of FeRh. As often occurs upon alloying, and despite the good crystallinity of the layer, <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>κ</mi></math> was found to be lower than the thermal conductivities of its constituting elements. More unexpectedly, given the electrically more conducting nature of the FM phase, it turned out to be three times lower in the FM phase compared to the AFM phase. This trend was confirmed by examining the temporal decay of incoherent phonons generated by a pulsed laser in both phases. To elucidate these results, first- and second-principles simulations were performed to estimate the phonon, magnon, and electron contributions to the thermal conductivity. They were found to be of the same order of magnitude, and to give a quantitative rendering of the experimentally observed <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>κ</mi><mi>AFM</mi></msub></math>. In the FM phase, however, simulations overestimate the low experimental values, implying very different (shorter) electron and magnon lifetimes.","PeriodicalId":20545,"journal":{"name":"Physical Review Materials","volume":"2 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142206131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-27DOI: 10.1103/physrevmaterials.8.084203
Tiema Qian, Chaowei Hu, J. Green, Erxi Feng, Huibo Cao, Ni Ni
Magnetic topological insulators provide a platform for emergent phenomena arising from the interplay between magnetism and band topology. Here we report the single crystal growth, crystal structure, magnetic and transport properties, as well as the neutron scattering studies of topological insulator series . Upon doping up to , the lattice parameter decreases by 0.8%, while the lattice parameter remains nearly unchanged. Significant Ge vacancies and Ge/Bi site mixing are revealed via elemental analysis as well as refinements of the neutron and x-ray diffraction data, resulting in holes dominating the charge transport. At , below 10.8 K, a bilayer A-type antiferromagnetic ordered state emerges, featuring an ordered moment of 3.0(3) at 5 K, with the axis as the easy axis. Magnetization data unveils a much stronger effective interlayer antiferromagnetic exchange interaction and a much smaller uniaxial anisotropy compared to . We attribute the former to the shorter nearest-neighbor Mn-Mn interlayer superexchange path and the latter to the smaller ligand-field splitting in . Our study demonstrates that this series of materials holds promise for the investigation of the layer Hall effect and quantum metric nonlinear Hall effect.
磁性拓扑绝缘体为磁性和带拓扑之间的相互作用所产生的新现象提供了一个平台。在此，我们报告了拓扑绝缘体系列 (Ge1-δ-xMnx)2Bi2Te5 (x≤0.47, 0.11≤δ≤0.20) 的单晶生长、晶体结构、磁性和输运性质以及中子散射研究。掺杂到 x=0.47 时，晶格参数 c 下降了 0.8%，而晶格参数 a 几乎保持不变。通过元素分析以及对中子和 X 射线衍射数据的改进，发现了大量的 Ge 空位和 Ge/Bi 位点混合，从而导致空穴主导了电荷传输。在 x=0.47 时，温度低于 10.8 K，出现了双层 A 型反铁磁有序态，5 K 时的有序矩为 3.0(3) μB/Mn，c 轴为易轴。与锰铋碲 4 相比，磁化数据揭示了更强的有效层间反铁磁交换相互作用和更小的单轴各向异性。我们将前者归因于更短的近邻锰-锰层间超交换路径，将后者归因于 (Ge1-δ-xMnx)2Bi2Te5 中更小的配位体-场分裂。我们的研究表明，这一系列材料有望用于研究层霍尔效应和量子度量非线性霍尔效应。
{"title":"Single crystal growth, chemical defects, magnetic and transport properties of antiferromagnetic topological insulators (Ge1−δ−xMnx)2Bi2Te5 (x≤0.47, 0.11≤δ≤0.20)","authors":"Tiema Qian, Chaowei Hu, J. Green, Erxi Feng, Huibo Cao, Ni Ni","doi":"10.1103/physrevmaterials.8.084203","DOIUrl":"https://doi.org/10.1103/physrevmaterials.8.084203","url":null,"abstract":"Magnetic topological insulators provide a platform for emergent phenomena arising from the interplay between magnetism and band topology. Here we report the single crystal growth, crystal structure, magnetic and transport properties, as well as the neutron scattering studies of topological insulator series <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mrow><mo>(</mo><msub><mi>Ge</mi><mrow><mn>1</mn><mo>−</mo><mi>δ</mi><mo>−</mo><mi>x</mi></mrow></msub><msub><mi>Mn</mi><mi>x</mi></msub><mo>)</mo></mrow><mn>2</mn></msub><msub><mi>Bi</mi><mn>2</mn></msub><msub><mi>Te</mi><mn>5</mn></msub></mrow></math> <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mo>(</mo><mi>x</mi><mo>≤</mo><mn>0.47</mn></mrow><mo>,</mo><mo> </mo><mrow><mn>0.11</mn><mo>≤</mo><mi>δ</mi><mo>≤</mo><mn>0.20</mn><mo>)</mo></mrow></math>. Upon doping up to <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>x</mi><mo>=</mo><mn>0.47</mn></mrow></math>, the lattice parameter <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>c</mi></math> decreases by 0.8%, while the lattice parameter <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>a</mi></math> remains nearly unchanged. Significant Ge vacancies and Ge/Bi site mixing are revealed via elemental analysis as well as refinements of the neutron and x-ray diffraction data, resulting in holes dominating the charge transport. At <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>x</mi><mo>=</mo><mn>0.47</mn></mrow></math>, below 10.8 K, a bilayer A-type antiferromagnetic ordered state emerges, featuring an ordered moment of 3.0(3) <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>μ</mi><mi>B</mi></msub><mo>/</mo><mi>Mn</mi></mrow></math> at 5 K, with the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>c</mi></math> axis as the easy axis. Magnetization data unveils a much stronger effective interlayer antiferromagnetic exchange interaction and a much smaller uniaxial anisotropy compared to <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>MnBi</mi><mn>2</mn></msub><msub><mi>Te</mi><mn>4</mn></msub></mrow></math>. We attribute the former to the shorter nearest-neighbor Mn-Mn interlayer superexchange path and the latter to the smaller ligand-field splitting in <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mrow><mo>(</mo><msub><mi>Ge</mi><mrow><mn>1</mn><mo>−</mo><mi>δ</mi><mo>−</mo><mi>x</mi></mrow></msub><msub><mi>Mn</mi><mi>x</mi></msub><mo>)</mo></mrow><mn>2</mn></msub><msub><mi>Bi</mi><mn>2</mn></msub><msub><mi>Te</mi><mn>5</mn></msub></mrow></math>. Our study demonstrates that this series of materials holds promise for the investigation of the layer Hall effect and quantum metric nonlinear Hall effect.","PeriodicalId":20545,"journal":{"name":"Physical Review Materials","volume":"68 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142206133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-26DOI: 10.1103/physrevmaterials.8.083801
Andy Paul Chen, Wei Nong, Maung Thway, Jose Recatala-Gomez, Haiwen Dai, Wenhao Zhai, D. V. Maheswar Repaka, Kedar Hippalgaonkar
Chalcopyrites are ternary crystalline compounds which have found use in a diverse array of applications, from solar cells to thermoelectric devices. These are known to be ternary-compound analogs to diamond or sphalerite. “Defect chalcopyrites,” which are chalcopyrite structures stabilized with ordered vacancies and substitutions, are well attested and can serve as a method of tuning material properties through control of stoichiometry. In particular, defect chalcopyrites related to the thermoelectric compound comprise a large range of compositions in the pseudobinary system , where . In contrast, the converse case of “augmented chalcopyrites,” namely, , is much less known or studied. We report the discovery of a range of -rich compositions in this binary system where stable phases can potentially be found. Here, the stoichometry of augmented chalcopyrites is likely to be modulated by the concentration of defect clusters in chalcopyrite .
{"title":"Augmented chalcopyrites: A search for new Cu-In-Te phases","authors":"Andy Paul Chen, Wei Nong, Maung Thway, Jose Recatala-Gomez, Haiwen Dai, Wenhao Zhai, D. V. Maheswar Repaka, Kedar Hippalgaonkar","doi":"10.1103/physrevmaterials.8.083801","DOIUrl":"https://doi.org/10.1103/physrevmaterials.8.083801","url":null,"abstract":"Chalcopyrites are ternary crystalline compounds which have found use in a diverse array of applications, from solar cells to thermoelectric devices. These are known to be ternary-compound analogs to diamond or sphalerite. “Defect chalcopyrites,” which are chalcopyrite structures stabilized with ordered vacancies and substitutions, are well attested and can serve as a method of tuning material properties through control of stoichiometry. In particular, defect chalcopyrites related to the thermoelectric compound <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>CuInTe</mi><mn>2</mn></msub></math> comprise a large range of compositions in the pseudobinary system <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mrow><mo>(</mo><msub><mi>Cu</mi><mn>2</mn></msub><mi>Te</mi><mo>)</mo></mrow><mi>x</mi></msub><msub><mrow><mo>(</mo><msub><mi>In</mi><mn>2</mn></msub><msub><mi>Te</mi><mn>3</mn></msub><mo>)</mo></mrow><mrow><mn>1</mn><mo>−</mo><mi>x</mi></mrow></msub></mrow></math>, where <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>x</mi><mo><</mo><mn>0.5</mn></mrow></math>. In contrast, the converse case of “augmented chalcopyrites,” namely, <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>x</mi><mo>></mo><mn>0.5</mn></mrow></math>, is much less known or studied. We report the discovery of a range of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>Cu</mi><mn>2</mn></msub><mi>Te</mi></mrow></math>-rich compositions in this binary system where stable phases can potentially be found. Here, the stoichometry of augmented chalcopyrites is likely to be modulated by the concentration of defect clusters <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mrow><mo>[</mo><msubsup><mrow><mi>Cu</mi></mrow><mtext>In</mtext><mrow><mn>2</mn><mo>−</mo></mrow></msubsup><mo>·</mo><mn>2</mn><msubsup><mi>Cu</mi><mi>i</mi><mo>+</mo></msubsup><mo>]</mo></mrow><mn>0</mn></msup></math> in chalcopyrite <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>CuInTe</mi><mn>2</mn></msub></math>.","PeriodicalId":20545,"journal":{"name":"Physical Review Materials","volume":"45 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142206130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-23DOI: 10.1103/physrevmaterials.8.085403
Dusan Lorenc, Ayan Zhumekenov, Osman M. Bakr, Zhanybek Alpichshev
Lead halide perovskites have recently been reported to demonstrate an exceptionally high nonlinear (Kerr) refractive index of up to in . Other researchers, however, observe different, substantially more conservative numbers. In order to resolve this disagreement, the nonlinear Kerr index of a bulk sample of lead halide perovskite was measured directly by means of an interferometer. This approach has many advantages as compared to the more standard z-scan technique. In particular, this method allows studying the induced changes to the refractive index in a time-resolved manner, thus enabling to separate the different contributions to . The extracted values for and at are and , respectively. Hence, these values are substantially lower than what has been indicated in most of the previous reports, implying the latter one should be regarded with great care.
{"title":"No extraordinary χ(3) in lead-halide perovskites: placing an upper bound on Kerr nonlinearity by means of time-resolved interferometry","authors":"Dusan Lorenc, Ayan Zhumekenov, Osman M. Bakr, Zhanybek Alpichshev","doi":"10.1103/physrevmaterials.8.085403","DOIUrl":"https://doi.org/10.1103/physrevmaterials.8.085403","url":null,"abstract":"Lead halide perovskites have recently been reported to demonstrate an exceptionally high nonlinear (Kerr) refractive index <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi mathvariant=\"normal\">n</mi><mn>2</mn></msub></math> of up to <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msup><mn>10</mn><mrow><mo>−</mo><mn>8</mn></mrow></msup><mspace width=\"4pt\"></mspace><msup><mrow><mi>cm</mi></mrow><mn>2</mn></msup><mo>/</mo><mi mathvariant=\"normal\">W</mi></mrow></math> in <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>CH</mi><mn>3</mn></msub><msub><mi>NH</mi><mn>3</mn></msub><msub><mi>PbBr</mi><mn>3</mn></msub></mrow></math>. Other researchers, however, observe different, substantially more conservative numbers. In order to resolve this disagreement, the nonlinear Kerr index of a bulk sample of lead halide perovskite was measured directly by means of an interferometer. This approach has many advantages as compared to the more standard z-scan technique. In particular, this method allows studying the induced changes to the refractive index in a time-resolved manner, thus enabling to separate the different contributions to <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>n</mi><mn>2</mn></msub></math>. The extracted <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi mathvariant=\"italic\">n</mi><mn>2</mn></msub></math> values for <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>CsPbBr</mi><mn>3</mn></msub></math> and <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>MAPbBr</mi><mn>3</mn></msub></math> at <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>λ</mi><mo>≈</mo><mn>1</mn><mspace width=\"0.16em\"></mspace><mi>µ</mi><mi mathvariant=\"normal\">m</mi></mrow></math> are <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>n</mi><mn>2</mn></msub><mo>=</mo><mo>+</mo><mn>2.1</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>14</mn></mrow></msup><mspace width=\"4pt\"></mspace><msup><mrow><mi>cm</mi></mrow><mn>2</mn></msup><mo>/</mo><mi mathvariant=\"normal\">W</mi></mrow></math> and <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>n</mi><mn>2</mn></msub><mo>=</mo><mo>+</mo><mn>6</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>15</mn></mrow></msup><mspace width=\"4pt\"></mspace><msup><mrow><mi>cm</mi></mrow><mn>2</mn></msup><mo>/</mo><mi mathvariant=\"normal\">W</mi></mrow></math>, respectively. Hence, these values are substantially lower than what has been indicated in most of the previous reports, implying the latter one should be regarded with great care.","PeriodicalId":20545,"journal":{"name":"Physical Review Materials","volume":"66 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142206138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-23DOI: 10.1103/physrevmaterials.8.084410
Andrew F. May, Eleanor M. Clements, Xiaoping Wang, Heda Zhang, Brenden R. Ortiz
The hexagonal <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>Eu</mi><mi>M</mi><mi>X</mi></mrow></math> <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mo>(</mo><mi>M</mi><mo>=</mo><mi>Cu</mi><mo>,</mo><mo> </mo><mi>Ag</mi><mo>,</mo><mo> </mo><mi>Au</mi><mo>;</mo><mo> </mo><mi>X</mi><mo>=</mo><mi mathvariant="normal">P</mi><mo>,</mo><mo> </mo><mi>As</mi><mo>,</mo><mo> </mo><mi>Sb</mi><mo>,</mo><mo> </mo><mi>Bi</mi><mo>)</mo></mrow></math> compounds host interesting electronic and magnetic properties, with seemingly intertwined topology and transport properties. One key feature of such behavior is the nature of the ordered magnetic structure. In EuCuAs, a topological Hall effect is caused by a conical spin structure that emerges when a field is applied within the easy-plane <math xmlns="http://www.w3.org/1998/Math/MathML"><mo>(</mo><mi>H</mi></math> <math xmlns="http://www.w3.org/1998/Math/MathML"><mo>⊥</mo></math> <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>c</mi><mo>)</mo></math> of the helical ground state that exists below the Neel temperature of <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msub><mi>T</mi><mi>N</mi></msub><mo>=</mo><mn>14</mn><mspace width="0.16em"></mspace><mi mathvariant="normal">K</mi></mrow></math>. On the other hand, EuCuP is an easy-axis ferromagnet with a Curie temperature <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>T</mi><mi>C</mi></msub></math> near 31 K. Here, we investigate the evolution of the magnetic properties in <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msub><mi>EuCuAs</mi><mrow><mn>1</mn><mo>−</mo><mi>x</mi></mrow></msub><msub><mi mathvariant="normal">P</mi><mi>x</mi></msub></mrow></math> single crystals with <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mn>0.16</mn><mo> </mo><mo>≤</mo><mi>x</mi><mo>≤</mo><mo> </mo><mn>0.75</mn></mrow></math>. Crystals grown by cooling slowly in a Sn flux possessed macroscale inhomogeneity of As/P, particularly for arsenic-rich crystals. However, growth in a Sn flux via an isothermal dwell at <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mn>600</mn><msup><mspace width="0.16em"></mspace><mo>∘</mo></msup><mi mathvariant="normal">C</mi></mrow></math> produced crystals that were homogeneous within the resolution of the probes utilized to investigate these crystals. The unit cell volumes, Curie-Weiss temperatures, and magnetic transitions trend linearly with composition and the magnetic anisotropy is reduced in the alloys. The magnetization data of crystals with <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>x</mi><mo>=</mo><mn>0.16</mn></mrow></math> and 0.24 indicate an easy-plane antiferromagnetic ground state while behavior similar to ferromagnetism is observed for crystals with <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>x</mi><mspace width="4pt"></mspace><mo>≥</mo><mo> </mo><mn>0.41</mn></mrow></math>. The temperature-dependent magnetization data possess multiple
{"title":"Crystal growth and evolution of magnetism in the EuCuP-EuCuAs solid solution","authors":"Andrew F. May, Eleanor M. Clements, Xiaoping Wang, Heda Zhang, Brenden R. Ortiz","doi":"10.1103/physrevmaterials.8.084410","DOIUrl":"https://doi.org/10.1103/physrevmaterials.8.084410","url":null,"abstract":"The hexagonal <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>Eu</mi><mi>M</mi><mi>X</mi></mrow></math> <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mo>(</mo><mi>M</mi><mo>=</mo><mi>Cu</mi><mo>,</mo><mo> </mo><mi>Ag</mi><mo>,</mo><mo> </mo><mi>Au</mi><mo>;</mo><mo> </mo><mi>X</mi><mo>=</mo><mi mathvariant=\"normal\">P</mi><mo>,</mo><mo> </mo><mi>As</mi><mo>,</mo><mo> </mo><mi>Sb</mi><mo>,</mo><mo> </mo><mi>Bi</mi><mo>)</mo></mrow></math> compounds host interesting electronic and magnetic properties, with seemingly intertwined topology and transport properties. One key feature of such behavior is the nature of the ordered magnetic structure. In EuCuAs, a topological Hall effect is caused by a conical spin structure that emerges when a field is applied within the easy-plane <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mo>(</mo><mi>H</mi></math> <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mo>⊥</mo></math> <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>c</mi><mo>)</mo></math> of the helical ground state that exists below the Neel temperature of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>T</mi><mi>N</mi></msub><mo>=</mo><mn>14</mn><mspace width=\"0.16em\"></mspace><mi mathvariant=\"normal\">K</mi></mrow></math>. On the other hand, EuCuP is an easy-axis ferromagnet with a Curie temperature <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>T</mi><mi>C</mi></msub></math> near 31 K. Here, we investigate the evolution of the magnetic properties in <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>EuCuAs</mi><mrow><mn>1</mn><mo>−</mo><mi>x</mi></mrow></msub><msub><mi mathvariant=\"normal\">P</mi><mi>x</mi></msub></mrow></math> single crystals with <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>0.16</mn><mo> </mo><mo>≤</mo><mi>x</mi><mo>≤</mo><mo> </mo><mn>0.75</mn></mrow></math>. Crystals grown by cooling slowly in a Sn flux possessed macroscale inhomogeneity of As/P, particularly for arsenic-rich crystals. However, growth in a Sn flux via an isothermal dwell at <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>600</mn><msup><mspace width=\"0.16em\"></mspace><mo>∘</mo></msup><mi mathvariant=\"normal\">C</mi></mrow></math> produced crystals that were homogeneous within the resolution of the probes utilized to investigate these crystals. The unit cell volumes, Curie-Weiss temperatures, and magnetic transitions trend linearly with composition and the magnetic anisotropy is reduced in the alloys. The magnetization data of crystals with <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>x</mi><mo>=</mo><mn>0.16</mn></mrow></math> and 0.24 indicate an easy-plane antiferromagnetic ground state while behavior similar to ferromagnetism is observed for crystals with <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>x</mi><mspace width=\"4pt\"></mspace><mo>≥</mo><mo> </mo><mn>0.41</mn></mrow></math>. The temperature-dependent magnetization data possess multiple","PeriodicalId":20545,"journal":{"name":"Physical Review Materials","volume":"36 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142206134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-23DOI: 10.1103/physrevmaterials.8.085404
Avisek Maity, Sudipta Chatterjee, Barnali Ghosh, A. K. Raychaudhuri
We have investigated impedance, electric modulus, and dielectric spectroscopies, along with AC conductivity, on single crystals of methylammonium lead iodide (MAPI) and formamidinium lead iodide (FAPI) in the frequency range in the dark and under low-intensity illumination (). It is demonstrated that the relaxation observed in this frequency range in these single crystals can be attributed to space charge effects in the bulk of the crystals, which are caused by the finite time scale associated with charge relaxation, which can occur in this frequency range due to the large static dielectric constant and low conductivity of these solids. The relaxation was found to be faster in FAPI (with higher conductivity) compared to that in MAPI (with lower conductivity). The electron-hole pair generated by illumination enhances electronic conductivity and accelerates ionic migration by lowering the barrier; this, in turn, decreases the charge relaxation time and enhances the relaxation process. The barrier lowering inferred from the reduction in relaxation times by illumination is proposed to be associated with changes in the chemical potential attributed to carrier generation.
{"title":"Low-intensity illumination induced relaxation and charge transport behavior of single crystal halide perovskites","authors":"Avisek Maity, Sudipta Chatterjee, Barnali Ghosh, A. K. Raychaudhuri","doi":"10.1103/physrevmaterials.8.085404","DOIUrl":"https://doi.org/10.1103/physrevmaterials.8.085404","url":null,"abstract":"We have investigated impedance, electric modulus, and dielectric spectroscopies, along with AC conductivity, on single crystals of methylammonium lead iodide (MAPI) and formamidinium lead iodide (FAPI) in the frequency range <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>50</mn><mspace width=\"0.16em\"></mspace><mi>Hz</mi><mo>≤</mo><mi>f</mi><mo>≤</mo><mn>1</mn><mspace width=\"0.16em\"></mspace><mi>MHz</mi></mrow></math> in the dark and under low-intensity illumination (<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mo>≤</mo><mn>80</mn><mspace width=\"0.28em\"></mspace><mo>µ</mo><mi mathvariant=\"normal\">W</mi><mo>/</mo><msup><mrow><mi>cm</mi></mrow><mn>2</mn></msup></mrow></math>). It is demonstrated that the relaxation observed in this frequency range in these single crystals can be attributed to space charge effects in the bulk of the crystals, which are caused by the finite time scale associated with charge relaxation, which can occur in this frequency range due to the large static dielectric constant and low conductivity of these solids. The relaxation was found to be faster in FAPI (with higher conductivity) compared to that in MAPI (with lower conductivity). The electron-hole pair generated by illumination enhances electronic conductivity and accelerates ionic migration by lowering the barrier; this, in turn, decreases the charge relaxation time and enhances the relaxation process. The barrier lowering inferred from the reduction in relaxation times by illumination is proposed to be associated with changes in the chemical potential attributed to carrier generation.","PeriodicalId":20545,"journal":{"name":"Physical Review Materials","volume":"406 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142206132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Below , single-crystal FeSe undergoes a structural phase transition coinciding with the emergence of lattice domain boundaries, termed twin boundaries. Polarized-light microscopy validated the presence of twin boundaries in pristine FeSe and indicated the existence of extensive microsized twining in proton-irradiated FeSe. In twinned FeSe, vortex penetration displays a fractal, mazelike pattern, likely guided by these twin domains. We speculate substantial microtwinning in the proton-irradiation crystals, yet macroscopic twin boundaries persist as primary conduits for vortex motion.
{"title":"Vortex penetration along twin boundaries in pristine and proton-irradiated FeSe","authors":"Tong Ren, Yue Sun, Francesco Laviano, Ryousuke Sakagami, Zhi Xiang Shi, Tsuyoshi Tamegai","doi":"10.1103/physrevmaterials.8.084806","DOIUrl":"https://doi.org/10.1103/physrevmaterials.8.084806","url":null,"abstract":"Below <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>T</mi><mi mathvariant=\"normal\">s</mi></msub><mo>∼</mo><mn>90</mn><mspace width=\"0.28em\"></mspace><mi mathvariant=\"normal\">K</mi></mrow></math>, single-crystal FeSe undergoes a structural phase transition coinciding with the emergence of lattice domain boundaries, termed twin boundaries. Polarized-light microscopy validated the presence of twin boundaries in pristine FeSe and indicated the existence of extensive microsized twining in proton-irradiated FeSe. In twinned FeSe, vortex penetration displays a fractal, mazelike pattern, likely guided by these twin domains. We speculate substantial microtwinning in the proton-irradiation crystals, yet macroscopic twin boundaries persist as primary conduits for vortex motion.","PeriodicalId":20545,"journal":{"name":"Physical Review Materials","volume":"180 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142206136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-20DOI: 10.1103/physrevmaterials.8.085402
Kevin Ye, Matan Menahem, Tommaso Salzillo, Florian Knoop, Boyang Zhao, Shanyuan Niu, Olle Hellman, Jayakanth Ravichandran, R. Jaramillo, Omer Yaffe
We report a comparative study of temperature-dependent photoluminescence and structural dynamics of two perovskite semiconductors, the chalcogenide and the halide . These materials have similar crystal structures and direct band gaps, but we find that they have quite distinct optoelectronic and vibrational properties. Both materials exhibit thermally activated nonradiative recombination, but the nonradiative recombination rate in is four orders of magnitude faster than in , for the crystals studied here. Raman spectroscopy reveals that the effects of phonon anharmonicity are far more pronounced in than in . Further, although both materials feature a large dielectric response due to low-energy polar optical phonons, the phonons in are substantially lower in energy than in . Our results suggest that electron-phonon coupling in is more effective at nonradiative recombination than in and that may also have a substantially higher concentration of nonradiative recombination centers than . The low defect concentration in may be related to the ease of lattice reconfiguration, typified by anharmonic bonding. It remains to be seen to what extent these differences are inherent to the chalcogenide and halide perovskites and to what extent they can be affected by materials processing.
{"title":"Differing vibrational properties of halide and chalcogenide perovskite semiconductors and impact on optoelectronic performance","authors":"Kevin Ye, Matan Menahem, Tommaso Salzillo, Florian Knoop, Boyang Zhao, Shanyuan Niu, Olle Hellman, Jayakanth Ravichandran, R. Jaramillo, Omer Yaffe","doi":"10.1103/physrevmaterials.8.085402","DOIUrl":"https://doi.org/10.1103/physrevmaterials.8.085402","url":null,"abstract":"We report a comparative study of temperature-dependent photoluminescence and structural dynamics of two perovskite semiconductors, the chalcogenide <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>BaZrS</mi><mn>3</mn></msub></math> and the halide <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>Cs</mi><mi>Pb</mi><msub><mi>Br</mi><mn>3</mn></msub></mrow></math>. These materials have similar crystal structures and direct band gaps, but we find that they have quite distinct optoelectronic and vibrational properties. Both materials exhibit thermally activated nonradiative recombination, but the nonradiative recombination rate in <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>BaZrS</mi><mn>3</mn></msub></math> is four orders of magnitude faster than in <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>Cs</mi><mi>Pb</mi><msub><mi>Br</mi><mn>3</mn></msub></mrow></math>, for the crystals studied here. Raman spectroscopy reveals that the effects of phonon anharmonicity are far more pronounced in <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>Cs</mi><mi>Pb</mi><msub><mi>Br</mi><mn>3</mn></msub></mrow></math> than in <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>BaZrS</mi><mn>3</mn></msub></math>. Further, although both materials feature a large dielectric response due to low-energy polar optical phonons, the phonons in <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>Cs</mi><mi>Pb</mi><msub><mi>Br</mi><mn>3</mn></msub></mrow></math> are substantially lower in energy than in <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>BaZrS</mi><mn>3</mn></msub></math>. Our results suggest that electron-phonon coupling in <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>BaZrS</mi><mn>3</mn></msub></math> is more effective at nonradiative recombination than in <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>Cs</mi><mi>Pb</mi><msub><mi>Br</mi><mn>3</mn></msub></mrow></math> and that <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>BaZrS</mi><mn>3</mn></msub></math> may also have a substantially higher concentration of nonradiative recombination centers than <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>Cs</mi><mi>Pb</mi><msub><mi>Br</mi><mn>3</mn></msub></mrow></math>. The low defect concentration in <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>Cs</mi><mi>Pb</mi><msub><mi>Br</mi><mn>3</mn></msub></mrow></math> may be related to the ease of lattice reconfiguration, typified by anharmonic bonding. It remains to be seen to what extent these differences are inherent to the chalcogenide and halide perovskites and to what extent they can be affected by materials processing.","PeriodicalId":20545,"journal":{"name":"Physical Review Materials","volume":"57 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142206135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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