S. N. Holmes, C. W. Burrows, G. R. Bell, I. Farrer, D. A. Ritchie
The magneto-electronic properties of ferromagnetic MnSb grown by molecular beam epitaxy can be dominated by the presence of a surface state in the minority spin bandgap when the surface is Sb-terminated. The material resistivity is 120 µΩ.cm at 295 K, and although this is determined by the majority spin population, the anisotropic magnetoresistance, dependent on minority spins, is ∼0.24% for the Sb-terminated devices with Mn-terminated devices showing ∼0.02%. At 295 K, the extraordinary Hall constant is 0.5 Ω/T for the Sb-terminated surface and 1.5 Ω/T for the Mn-terminated surface with the extraordinary Hall constant and anisotropic magnetoresistance behaving with an anomalous temperature dependence between 295 and 1.5 K. The dominant MnSb structural phase on the GaAs (001) orientation is naturally doped p-type with a carrier density ∼1 × 1022 cm−3 determined by the normal Hall effect after the extraordinary Hall effect has saturated at higher fields than ∼2 T. Spintronic device possibilities are discussed, particularly the spin-light emitting diode and magnetic nano-structures. A natural p-type doping in MnSb limits the devices to dominant hole carrier effects although there is compatibility with both III–V and Si–Ge materials for hybrid device possibilities.
通过分子束外延生长的铁磁性锰锑的磁电特性，在表面以锑为端时，可能会受到少数自旋带隙中表面态存在的支配。在 295 K 时，材料的电阻率为 120 µΩ.cm，尽管这是由多数自旋群决定的，但取决于少数自旋的各向异性磁阻在 Sb 端器件中为 0.24%，而在 Mn 端器件中为 0.02%。在 295 K 时，Sb 端面的超常霍尔常数为 0.5 Ω/T，而 Mn 端面的超常霍尔常数为 1.5 Ω/T，超常霍尔常数和各向异性磁阻在 295 至 1.5 K 之间表现出反常的温度依赖性。砷化镓（001）取向上的主要 MnSb 结构相是自然掺杂的 p 型，其载流子密度 ∼1 × 1022 cm-3，是在非凡霍尔效应在高于 ∼2 T 的高场饱和后由正常霍尔效应确定的。锰锑中的天然 p 型掺杂限制了器件的主要空穴载流子效应，但它与 III-V 和 Si-Ge 材料兼容，可用于混合器件。
{"title":"Sb surface terminated MnSb devices in the niccolite phase","authors":"S. N. Holmes, C. W. Burrows, G. R. Bell, I. Farrer, D. A. Ritchie","doi":"10.1063/5.0181131","DOIUrl":"https://doi.org/10.1063/5.0181131","url":null,"abstract":"The magneto-electronic properties of ferromagnetic MnSb grown by molecular beam epitaxy can be dominated by the presence of a surface state in the minority spin bandgap when the surface is Sb-terminated. The material resistivity is 120 µΩ.cm at 295 K, and although this is determined by the majority spin population, the anisotropic magnetoresistance, dependent on minority spins, is ∼0.24% for the Sb-terminated devices with Mn-terminated devices showing ∼0.02%. At 295 K, the extraordinary Hall constant is 0.5 Ω/T for the Sb-terminated surface and 1.5 Ω/T for the Mn-terminated surface with the extraordinary Hall constant and anisotropic magnetoresistance behaving with an anomalous temperature dependence between 295 and 1.5 K. The dominant MnSb structural phase on the GaAs (001) orientation is naturally doped p-type with a carrier density ∼1 × 1022 cm−3 determined by the normal Hall effect after the extraordinary Hall effect has saturated at higher fields than ∼2 T. Spintronic device possibilities are discussed, particularly the spin-light emitting diode and magnetic nano-structures. A natural p-type doping in MnSb limits the devices to dominant hole carrier effects although there is compatibility with both III–V and Si–Ge materials for hybrid device possibilities.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"5 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139461978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Charlotte Wouters, Musbah Nofal, Piero Mazzolini, Jijun Zhang, Thilo Remmele, Albert Kwasniewski, Oliver Bierwagen, Martin Albrecht
In this paper, we employ in situ transmission electron microscopy to study the disorder–order phase transition from amorphous Ga2O3 to γ-Ga2O3 and then to β-Ga2O3. The in situ studies are complemented by ex situ annealing experiments, of which the results are analyzed by x-ray diffraction and high resolution (scanning) transmission electron microscopy. Amorphous Ga2O3 deposited at 100 °C by molecular beam epitaxy crystallizes at 470 °C in the γ phase (Fd3̄m), which undergoes a phase transition to the β phase above 500 °C. Between 500° and 900 °C, we find a mixture of γ-Ga2O3 and β-Ga2O3 coexisting. Above 950 °C, we find only β-Ga2O3. Through our analyses and by considering symmetry relations, we have constructed a coincidence site lattice of both structures containing a common fcc-type sublattice occupied by oxygen atoms, the cation sites of β-Ga2O3 common to both phases, and partially occupied cation sites in the γ phase corresponding to the interstitial sites in the β phase. We assign the atomic displacements within this lattice responsible for transforming the initially disordered spinel structure with partially occupied cation sites into the well-ordered lattice of β-Ga2O3. We identify this transition as a reconstructive disorder-to-order phase transition, mediated by the exchange of cations to next nearest neighbor sites. Our model not only explains recent observations of the formation of γ-Ga2O3 during implantation for n-type doping and the subsequent recovery of β-Ga2O3 following annealing but also holds potential for inspiring understanding in other materials with similar phase transitions.
{"title":"Unraveling the atomic mechanism of the disorder–order phase transition from γ-Ga2O3 to β-Ga2O3","authors":"Charlotte Wouters, Musbah Nofal, Piero Mazzolini, Jijun Zhang, Thilo Remmele, Albert Kwasniewski, Oliver Bierwagen, Martin Albrecht","doi":"10.1063/5.0182500","DOIUrl":"https://doi.org/10.1063/5.0182500","url":null,"abstract":"In this paper, we employ in situ transmission electron microscopy to study the disorder–order phase transition from amorphous Ga2O3 to γ-Ga2O3 and then to β-Ga2O3. The in situ studies are complemented by ex situ annealing experiments, of which the results are analyzed by x-ray diffraction and high resolution (scanning) transmission electron microscopy. Amorphous Ga2O3 deposited at 100 °C by molecular beam epitaxy crystallizes at 470 °C in the γ phase (Fd3̄m), which undergoes a phase transition to the β phase above 500 °C. Between 500° and 900 °C, we find a mixture of γ-Ga2O3 and β-Ga2O3 coexisting. Above 950 °C, we find only β-Ga2O3. Through our analyses and by considering symmetry relations, we have constructed a coincidence site lattice of both structures containing a common fcc-type sublattice occupied by oxygen atoms, the cation sites of β-Ga2O3 common to both phases, and partially occupied cation sites in the γ phase corresponding to the interstitial sites in the β phase. We assign the atomic displacements within this lattice responsible for transforming the initially disordered spinel structure with partially occupied cation sites into the well-ordered lattice of β-Ga2O3. We identify this transition as a reconstructive disorder-to-order phase transition, mediated by the exchange of cations to next nearest neighbor sites. Our model not only explains recent observations of the formation of γ-Ga2O3 during implantation for n-type doping and the subsequent recovery of β-Ga2O3 following annealing but also holds potential for inspiring understanding in other materials with similar phase transitions.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"13 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139461981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jingyu Tang, Kunyao Jiang, Chengchao Xu, Matthew J. Cabral, Kelly Xiao, Lisa M. Porter, Robert F. Davis
Nominally phase-pure γ-Ga2O3 was deposited on (100) MgAl2O4 within a narrow temperature window centered at ∼470 °C using metal-organic chemical vapor deposition. The film deposited at 440 °C exhibited either poor crystallization or an amorphous structure; the film grown at 500 °C contained both β-Ga2O3 and γ-Ga2O3. A nominally phase-pure β-Ga2O3 film was obtained at 530 °C. Atomic-resolution scanning transmission electron microscopy (STEM) investigations of the γ-Ga2O3 film grown at 470 °C revealed a high density of antiphase boundaries. A planar defect model developed for γ-Al2O3 was extended to explain the stacking sequences of the Ga sublattice observed in the STEM images of γ-Ga2O3. The presence of the 180° rotational domains and 90° rotational domains of β-Ga2O3 inclusions within the γ-Ga2O3 matrix is discussed within the context of a comprehensive investigation of the epitaxial relationship between those two phases in the as-grown film at 470 °C and the same film annealed at 600 °C. The results led to the hypotheses that (i) incorporation of certain dopants, including Si, Ge, Sn, Mg, Al, and Sc, into β-Ga2O3 locally stabilizes the “γ-phase” and (ii) the site preference(s) for these dopants promotes the formation of “γ-phase” and/or γ-Ga2O3 solid solutions. However, in the absence of such dopants, pure γ-Ga2O3 remains the least stable Ga2O3 polymorph, as indicated by its very narrow growth window, lower growth temperatures relative to other Ga2O3 polymorphs, and the largest calculated difference in Helmholtz free energy per formula unit between γ-Ga2O3 and β-Ga2O3 than all other polymorphs.
{"title":"Atomic-scale investigation of γ-Ga2O3 deposited on MgAl2O4 and its relationship with β-Ga2O3","authors":"Jingyu Tang, Kunyao Jiang, Chengchao Xu, Matthew J. Cabral, Kelly Xiao, Lisa M. Porter, Robert F. Davis","doi":"10.1063/5.0180922","DOIUrl":"https://doi.org/10.1063/5.0180922","url":null,"abstract":"Nominally phase-pure γ-Ga2O3 was deposited on (100) MgAl2O4 within a narrow temperature window centered at ∼470 °C using metal-organic chemical vapor deposition. The film deposited at 440 °C exhibited either poor crystallization or an amorphous structure; the film grown at 500 °C contained both β-Ga2O3 and γ-Ga2O3. A nominally phase-pure β-Ga2O3 film was obtained at 530 °C. Atomic-resolution scanning transmission electron microscopy (STEM) investigations of the γ-Ga2O3 film grown at 470 °C revealed a high density of antiphase boundaries. A planar defect model developed for γ-Al2O3 was extended to explain the stacking sequences of the Ga sublattice observed in the STEM images of γ-Ga2O3. The presence of the 180° rotational domains and 90° rotational domains of β-Ga2O3 inclusions within the γ-Ga2O3 matrix is discussed within the context of a comprehensive investigation of the epitaxial relationship between those two phases in the as-grown film at 470 °C and the same film annealed at 600 °C. The results led to the hypotheses that (i) incorporation of certain dopants, including Si, Ge, Sn, Mg, Al, and Sc, into β-Ga2O3 locally stabilizes the “γ-phase” and (ii) the site preference(s) for these dopants promotes the formation of “γ-phase” and/or γ-Ga2O3 solid solutions. However, in the absence of such dopants, pure γ-Ga2O3 remains the least stable Ga2O3 polymorph, as indicated by its very narrow growth window, lower growth temperatures relative to other Ga2O3 polymorphs, and the largest calculated difference in Helmholtz free energy per formula unit between γ-Ga2O3 and β-Ga2O3 than all other polymorphs.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"1 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139462008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
HfO2-based ferroelectric field-effect transistors (FeFETs) are regarded as one of the most promising non-volatile memory technologies in the future. However, the charge trapping phenomenon during the program/erase operation is still a challenge. In this work, we comprehensively investigate the behaviors of semiconductor/insulator interface charge trapping in HfO2-based FeFETs. Through analyzing the effects of the spatial distribution of interface traps and the polarization switching speed, the coupling effects of semiconductor/insulator interface charge trapping and polarization switching are recognized. We also find that the band tail state traps have much less influence on the electrical characteristics of the FeFETs than the deep level state traps. Through engineering the devices with band tail state traps with concentrations as small as possible, the influences of charge trapping could be effectively suppressed. Moreover, the gate voltage (VG) scanning rate has a significant influence on the interface charge trapping process due to the time dependent change of ferroelectric polarization. The largest memory window could be obtained by carefully choosing the VG scanning rate of the FeFETs based on the polarization switching speed. This work represents a key step for realizing highly reliable HfO2-based FeFETs.
{"title":"Coupling effects of interface charge trapping and polarization switching in HfO2-based ferroelectric field effect transistors","authors":"Tianqi Hao, Binjian Zeng, Zhijie Sun, Zhenguo Wang, Yongquan Jiang, Qiangxiang Peng, Shuaizhi Zheng, Yichun Zhou, Min Liao","doi":"10.1063/5.0184042","DOIUrl":"https://doi.org/10.1063/5.0184042","url":null,"abstract":"HfO2-based ferroelectric field-effect transistors (FeFETs) are regarded as one of the most promising non-volatile memory technologies in the future. However, the charge trapping phenomenon during the program/erase operation is still a challenge. In this work, we comprehensively investigate the behaviors of semiconductor/insulator interface charge trapping in HfO2-based FeFETs. Through analyzing the effects of the spatial distribution of interface traps and the polarization switching speed, the coupling effects of semiconductor/insulator interface charge trapping and polarization switching are recognized. We also find that the band tail state traps have much less influence on the electrical characteristics of the FeFETs than the deep level state traps. Through engineering the devices with band tail state traps with concentrations as small as possible, the influences of charge trapping could be effectively suppressed. Moreover, the gate voltage (VG) scanning rate has a significant influence on the interface charge trapping process due to the time dependent change of ferroelectric polarization. The largest memory window could be obtained by carefully choosing the VG scanning rate of the FeFETs based on the polarization switching speed. This work represents a key step for realizing highly reliable HfO2-based FeFETs.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"4 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139462045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Metal-organic frameworks (MOFs) are porous crystalline materials. Their large pores make them particularly interesting for membranes, gas separation, and gas storage. Furthermore, MOFs are ultralight, making them suitable for a large realm of exciting applications ranging from wearable devices to space technology. Optimizing MOFs for these applications demands a detailed understanding of their low energy dynamics and photophysics, which can be provided by terahertz (THz) spectroscopy. MOFs exhibit structural modes, or phonons, with energies in the meV range, which corresponds to the THz spectral range (0.1–10 THz, 0.4–40 meV). Understanding these modes is crucial in determining how a MOF interacts with guest molecules in the process of gas capture and storage. In this perspective, we discuss how gas-MOF interactions alter the MOFs’ spectral fingerprints. We demonstrate that THz spectroscopy can be used for gas adsorption monitoring and explain how density functional theory, together with THz spectra, can illuminate the dynamic structure of MOFs, providing unique insight into their functionality. THz is also a contact free probe for conductivity and allows us to measure short range conductivity within an individual MOF crystal. We will discuss the advantages of THz as a conductivity probe for MOFs as compared to more established direct current techniques. We will then expand our view to incorporate ultrafast photoconductivity in MOFs measured via optical pump-THz probe spectroscopy, in comparison to more established ultrafast spectroscopic tools such as optical transient absorption and photoluminescence. We will supplement this section with a discussion of THz studies on perovskites, which unveiled electron–phonon interactions not yet explored in MOFs.
{"title":"Terahertz spectroscopy of MOFs reveals dynamic structure and contact free ultrafast photoconductivity","authors":"Kendra Hamilton, Jens Neu","doi":"10.1063/5.0179574","DOIUrl":"https://doi.org/10.1063/5.0179574","url":null,"abstract":"Metal-organic frameworks (MOFs) are porous crystalline materials. Their large pores make them particularly interesting for membranes, gas separation, and gas storage. Furthermore, MOFs are ultralight, making them suitable for a large realm of exciting applications ranging from wearable devices to space technology. Optimizing MOFs for these applications demands a detailed understanding of their low energy dynamics and photophysics, which can be provided by terahertz (THz) spectroscopy. MOFs exhibit structural modes, or phonons, with energies in the meV range, which corresponds to the THz spectral range (0.1–10 THz, 0.4–40 meV). Understanding these modes is crucial in determining how a MOF interacts with guest molecules in the process of gas capture and storage. In this perspective, we discuss how gas-MOF interactions alter the MOFs’ spectral fingerprints. We demonstrate that THz spectroscopy can be used for gas adsorption monitoring and explain how density functional theory, together with THz spectra, can illuminate the dynamic structure of MOFs, providing unique insight into their functionality. THz is also a contact free probe for conductivity and allows us to measure short range conductivity within an individual MOF crystal. We will discuss the advantages of THz as a conductivity probe for MOFs as compared to more established direct current techniques. We will then expand our view to incorporate ultrafast photoconductivity in MOFs measured via optical pump-THz probe spectroscopy, in comparison to more established ultrafast spectroscopic tools such as optical transient absorption and photoluminescence. We will supplement this section with a discussion of THz studies on perovskites, which unveiled electron–phonon interactions not yet explored in MOFs.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"68 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139422146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Magnetic domain walls (DWs) are the finite boundaries that separate the regions of uniform magnetization in a magnetic material. They constitute a key research topic in condensed matter physics due to their intriguing physics and relevance in technological applications. A multitude of spintronic concepts for memory, logic, and data processing applications have been proposed, relying on the precise control of DWs via magnetic fields and electric currents. Intensive research into DWs has also spurred interest into chiral magnetic interactions, topology, and relativistic physics. In this article, we will first review the rapid evolution of magnetic DW research and, in particular, the current-driven DW motion enabled by the improved understanding of DW dynamics and the development of suitable ferrimagnetic thin films. We will then provide an outlook on future directions in DW dynamics research exploiting ferrimagnetic garnets as a tunable material platform.
{"title":"Domain walls speed up in insulating ferrimagnetic garnets","authors":"Lucas Caretta, Can Onur Avci","doi":"10.1063/5.0159669","DOIUrl":"https://doi.org/10.1063/5.0159669","url":null,"abstract":"Magnetic domain walls (DWs) are the finite boundaries that separate the regions of uniform magnetization in a magnetic material. They constitute a key research topic in condensed matter physics due to their intriguing physics and relevance in technological applications. A multitude of spintronic concepts for memory, logic, and data processing applications have been proposed, relying on the precise control of DWs via magnetic fields and electric currents. Intensive research into DWs has also spurred interest into chiral magnetic interactions, topology, and relativistic physics. In this article, we will first review the rapid evolution of magnetic DW research and, in particular, the current-driven DW motion enabled by the improved understanding of DW dynamics and the development of suitable ferrimagnetic thin films. We will then provide an outlook on future directions in DW dynamics research exploiting ferrimagnetic garnets as a tunable material platform.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"56 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139409809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. Formisano, T. T. Gareev, D. I. Khusyainov, A. E. Fedianin, R. M. Dubrovin, P. P. Syrnikov, D. Afanasiev, R. V. Pisarev, A. M. Kalashnikova, J. H. Mentink, A. V. Kimel
Controlled generation of coherent spin waves with highest possible frequencies and shortest possible wavelengths is a cornerstone of spintronics and magnonics. Here, using Heisenberg antiferromagnet RbMnF3, we demonstrate that laser-induced THz spin dynamics corresponding to pairs of mutually coherent counter-propagating spin waves with the wavevectors up to the edge of the Brillouin zone cannot be understood in terms of magnetization and antiferromagnetic (Néel) vectors, conventionally used to describe spin waves. Instead, we propose to model such spin dynamics using the spin correlation function. We derive a quantum-mechanical equation of motion for the latter and emphasize that unlike the magnetization and antiferromagnetic vectors the spin correlations in antiferromagnets do not exhibit inertia.
{"title":"Coherent THz spin dynamics in antiferromagnets beyond the approximation of the Néel vector","authors":"F. Formisano, T. T. Gareev, D. I. Khusyainov, A. E. Fedianin, R. M. Dubrovin, P. P. Syrnikov, D. Afanasiev, R. V. Pisarev, A. M. Kalashnikova, J. H. Mentink, A. V. Kimel","doi":"10.1063/5.0180888","DOIUrl":"https://doi.org/10.1063/5.0180888","url":null,"abstract":"Controlled generation of coherent spin waves with highest possible frequencies and shortest possible wavelengths is a cornerstone of spintronics and magnonics. Here, using Heisenberg antiferromagnet RbMnF3, we demonstrate that laser-induced THz spin dynamics corresponding to pairs of mutually coherent counter-propagating spin waves with the wavevectors up to the edge of the Brillouin zone cannot be understood in terms of magnetization and antiferromagnetic (Néel) vectors, conventionally used to describe spin waves. Instead, we propose to model such spin dynamics using the spin correlation function. We derive a quantum-mechanical equation of motion for the latter and emphasize that unlike the magnetization and antiferromagnetic vectors the spin correlations in antiferromagnets do not exhibit inertia.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"21 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139409806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Helena Reichlova, Dominik Kriegner, Alexander Mook, Matthias Althammer, Andy Thomas
Topology plays a crucial and multifaceted role in solid state physics, leading to a remarkable array of newly investigated materials and phenomena. In this Perspective, we provide a brief summary of well-established model materials with a particular focus on compensated magnets and highlight key phenomena that emerge due to the influence of topology in these systems. The overview covers various magneto-transport phenomena, with a particular focus on the extensively investigated anomalous magneto-transport effects. Furthermore, we look into the significance of topology in understanding elementary magnetic excitations, namely magnons, where the role of topology gained considerable attention from both theoretical and experimental perspectives. Since electrons and magnons carry energy, we explore the implications of topology in combined heat and spin transport experiments in compensated magnetic systems. At the end of each section, we highlight intriguing unanswered questions in this research direction. To finally conclude, we offer our perspective on what could be the next advancements regarding the interaction between compensated magnetism and topology.
{"title":"Role of topology in compensated magnetic systems","authors":"Helena Reichlova, Dominik Kriegner, Alexander Mook, Matthias Althammer, Andy Thomas","doi":"10.1063/5.0161132","DOIUrl":"https://doi.org/10.1063/5.0161132","url":null,"abstract":"Topology plays a crucial and multifaceted role in solid state physics, leading to a remarkable array of newly investigated materials and phenomena. In this Perspective, we provide a brief summary of well-established model materials with a particular focus on compensated magnets and highlight key phenomena that emerge due to the influence of topology in these systems. The overview covers various magneto-transport phenomena, with a particular focus on the extensively investigated anomalous magneto-transport effects. Furthermore, we look into the significance of topology in understanding elementary magnetic excitations, namely magnons, where the role of topology gained considerable attention from both theoretical and experimental perspectives. Since electrons and magnons carry energy, we explore the implications of topology in combined heat and spin transport experiments in compensated magnetic systems. At the end of each section, we highlight intriguing unanswered questions in this research direction. To finally conclude, we offer our perspective on what could be the next advancements regarding the interaction between compensated magnetism and topology.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"15 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139409790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anett Jannasch, Cindy Welzel, Jessica Pablik, Elizabeth von Hauff, Roberta Galli, Jan Rix, Antje Schauer, Claudia Dittfeld, Sems-Malte Tugtekin
Glutaraldehyde (GA)-treated bovine pericardium is still the gold standard for the fabrication of bioprostheses needed for the surgical treatment of valvular malfunction. Although excellent stability and low immunogenicity are accomplished, the application of GA is considered to be causal for structural valve deterioration, diminishing the long-term durability of bioprosthetic tissue. The novel GA-free SULEEI-treatment of bovine pericardium combines decellularization, riboflavin/UVA-cross-linking, and low-energy electron beam irradiation. In the present study, we initiated an in vivo application. We used a subcutaneous rat model to compare the immune and tissue responses, calcification propensity, and biomechanical properties of the alternatively prepared SULEEI bovine pericardial tissue with standard glutaraldehyde-fixed and industrially produced bovine pericardial patch material. SULEEI pericardium evokes a similar immune reaction and tissue response as the control standard bovine patch material. The calcification propensity of SULEEI tissue was low, and biomechanical analysis revealed a heterogeneous but similar pattern in tissue stiffness compared to the control patch. The results of this study highlight the potential of SULEEI-treated bovine pericardial tissue as a candidate for cutting-edge cardiovascular and valvular biomaterials in reconstructive surgery.
{"title":"In vivo application of a glutaraldehyde-free, UVA/riboflavin cross-linked bovine pericardium confirms suitability for cardiovascular substitutes","authors":"Anett Jannasch, Cindy Welzel, Jessica Pablik, Elizabeth von Hauff, Roberta Galli, Jan Rix, Antje Schauer, Claudia Dittfeld, Sems-Malte Tugtekin","doi":"10.1063/5.0182672","DOIUrl":"https://doi.org/10.1063/5.0182672","url":null,"abstract":"Glutaraldehyde (GA)-treated bovine pericardium is still the gold standard for the fabrication of bioprostheses needed for the surgical treatment of valvular malfunction. Although excellent stability and low immunogenicity are accomplished, the application of GA is considered to be causal for structural valve deterioration, diminishing the long-term durability of bioprosthetic tissue. The novel GA-free SULEEI-treatment of bovine pericardium combines decellularization, riboflavin/UVA-cross-linking, and low-energy electron beam irradiation. In the present study, we initiated an in vivo application. We used a subcutaneous rat model to compare the immune and tissue responses, calcification propensity, and biomechanical properties of the alternatively prepared SULEEI bovine pericardial tissue with standard glutaraldehyde-fixed and industrially produced bovine pericardial patch material. SULEEI pericardium evokes a similar immune reaction and tissue response as the control standard bovine patch material. The calcification propensity of SULEEI tissue was low, and biomechanical analysis revealed a heterogeneous but similar pattern in tissue stiffness compared to the control patch. The results of this study highlight the potential of SULEEI-treated bovine pericardial tissue as a candidate for cutting-edge cardiovascular and valvular biomaterials in reconstructive surgery.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"48 6 Suppl 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139104290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jinhong Kim, Dane J. Sievers, Andrey E. Mironov, Sung-Jin Park, J. Gary Eden
Oxide films of the quality required for the fabrication of electronic and photonic devices are typically deposited at elevated temperatures and thermal equilibrium, thereby adversely impacting thermal budgets. We report the deposition and patterning of silicon dioxide (SiO2) films of high electrical and optical quality on Si(100) or polymer substrates in a N2 atmosphere and at 300 K by the photochemical conversion of thin liquid tetraethoxysilane (TEOS) layers with narrowband vacuum ultraviolet radiation [vacuum ultraviolet (VUV), 172 nm] provided by efficient microplasma lamps. Irradiating liquid TEOS layers, produced by spin-coating the precursor onto a substrate, with a VUV intensity of 13 mW cm−2, yields 40 nm-thick SiO2 films having a dielectric breakdown strength (Eb) of 5 MV cm−1, for which no precedent exists in the deposition of oxide films at 300 K. If room temperature-deposited films are post-annealed at 200 °C, Eb rises to 7.5 MV cm−1, which is <12% below the measured value (8.5 MV cm−1) for 40 nm SiO2 films grown by thermal oxidation. The deposition of 1 µm thick, stoichiometric SiO2 films requires only 20 min of VUV illumination at low optical fluences, and films with thicknesses of ∼35–60 nm exhibit a refractive index of 1.45 (633 nm). X-ray photoelectron spectrometry and Rutherford backscattering analysis indicate that, despite the deposition temperature, hydrocarbon impurity levels are near or below the detection limit. The capability for depositing 960 nm-thick SiO2 films uniformly (to within 0.6%) by liquid → solid photochemical conversion over a 5 cm diameter Si substrate and patterning films onto flexible polymer substrates has also been demonstrated.
{"title":"Uniform broad-area deposition and patterning of SiO2 nanofilms by 172 nm photochemical conversion of liquid tetraethoxysilane layers at 300 K","authors":"Jinhong Kim, Dane J. Sievers, Andrey E. Mironov, Sung-Jin Park, J. Gary Eden","doi":"10.1063/5.0177086","DOIUrl":"https://doi.org/10.1063/5.0177086","url":null,"abstract":"Oxide films of the quality required for the fabrication of electronic and photonic devices are typically deposited at elevated temperatures and thermal equilibrium, thereby adversely impacting thermal budgets. We report the deposition and patterning of silicon dioxide (SiO2) films of high electrical and optical quality on Si(100) or polymer substrates in a N2 atmosphere and at 300 K by the photochemical conversion of thin liquid tetraethoxysilane (TEOS) layers with narrowband vacuum ultraviolet radiation [vacuum ultraviolet (VUV), 172 nm] provided by efficient microplasma lamps. Irradiating liquid TEOS layers, produced by spin-coating the precursor onto a substrate, with a VUV intensity of 13 mW cm−2, yields 40 nm-thick SiO2 films having a dielectric breakdown strength (Eb) of 5 MV cm−1, for which no precedent exists in the deposition of oxide films at 300 K. If room temperature-deposited films are post-annealed at 200 °C, Eb rises to 7.5 MV cm−1, which is &lt;12% below the measured value (8.5 MV cm−1) for 40 nm SiO2 films grown by thermal oxidation. The deposition of 1 µm thick, stoichiometric SiO2 films requires only 20 min of VUV illumination at low optical fluences, and films with thicknesses of ∼35–60 nm exhibit a refractive index of 1.45 (633 nm). X-ray photoelectron spectrometry and Rutherford backscattering analysis indicate that, despite the deposition temperature, hydrocarbon impurity levels are near or below the detection limit. The capability for depositing 960 nm-thick SiO2 films uniformly (to within 0.6%) by liquid → solid photochemical conversion over a 5 cm diameter Si substrate and patterning films onto flexible polymer substrates has also been demonstrated.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":"1982 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139104517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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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