Pub Date : 2025-03-06DOI: 10.1016/j.physb.2025.417090
H. Yang , H.L. Shi , J. Yang , Q.Z. Han , Y.H. Zhao , L.J. Gong , Q.H. Liu , R.S. Cheng , Z.T. Jiang
Aiming at exploring materials of high thermoelectric (TE) performance, we systematically construct five SnTe monolayer allotropes including the -SnTe, -SnTe, and the newly designed -, -, and -SnTe. By using the first-principles calculations and nonequilibrium Green’s function method, their TE properties including the electrical conductance, the Seebeck coefficient, the power factor, the thermal conductance, and the figure of merit have been comparatively studied. For the -, -, -, and -SnTe monolayers, two peaks are observed near zero chemical potential and four peaks will be observed for the -SnTe monolayer. At room temperature, the maximum s of the -, -, and -SnTe monolayers are in the range from 1.5 to 2.0, and those of the - and -SnTe monolayers are greater than 4.0. As the temperature is increased to 700 K, the maximum s of all the five SnTe monolayers can be greater than 4.0 with the maximum of the -SnTe (-SnTe) being 7.51 (8.39) in the X direction. This indicates that the - and -SnTe monolayers can be used as the superior TE materials.
{"title":"Thermoelectric properties of five SnTe monolayer allotropes","authors":"H. Yang , H.L. Shi , J. Yang , Q.Z. Han , Y.H. Zhao , L.J. Gong , Q.H. Liu , R.S. Cheng , Z.T. Jiang","doi":"10.1016/j.physb.2025.417090","DOIUrl":"10.1016/j.physb.2025.417090","url":null,"abstract":"<div><div>Aiming at exploring materials of high thermoelectric (TE) performance, we systematically construct five SnTe monolayer allotropes including the <span><math><mi>α</mi></math></span>-SnTe, <span><math><mi>β</mi></math></span>-SnTe, and the newly designed <span><math><mi>γ</mi></math></span>-, <span><math><mi>δ</mi></math></span>-, and <span><math><mi>ɛ</mi></math></span>-SnTe. By using the first-principles calculations and nonequilibrium Green’s function method, their TE properties including the electrical conductance, the Seebeck coefficient, the power factor, the thermal conductance, and the figure of merit <span><math><mrow><mi>Z</mi><mi>T</mi></mrow></math></span> have been comparatively studied. For the <span><math><mi>α</mi></math></span>-, <span><math><mi>γ</mi></math></span>-, <span><math><mi>δ</mi></math></span>-, and <span><math><mi>ɛ</mi></math></span>-SnTe monolayers, two <span><math><mrow><mi>Z</mi><mi>T</mi></mrow></math></span> peaks are observed near zero chemical potential and four <span><math><mrow><mi>Z</mi><mi>T</mi></mrow></math></span> peaks will be observed for the <span><math><mi>β</mi></math></span>-SnTe monolayer. At room temperature, the maximum <span><math><mrow><mi>Z</mi><mi>T</mi></mrow></math></span>s of the <span><math><mi>α</mi></math></span>-, <span><math><mi>γ</mi></math></span>-, and <span><math><mi>δ</mi></math></span>-SnTe monolayers are in the range from 1.5 to 2.0, and those of the <span><math><mi>β</mi></math></span>- and <span><math><mi>ɛ</mi></math></span>-SnTe monolayers are greater than 4.0. As the temperature is increased to 700 K, the maximum <span><math><mrow><mi>Z</mi><mi>T</mi></mrow></math></span>s of all the five SnTe monolayers can be greater than 4.0 with the maximum <span><math><mrow><mi>Z</mi><mi>T</mi></mrow></math></span> of the <span><math><mi>β</mi></math></span>-SnTe (<span><math><mi>ɛ</mi></math></span>-SnTe) being 7.51 (8.39) in the X direction. This indicates that the <span><math><mi>β</mi></math></span>- and <span><math><mi>ɛ</mi></math></span>-SnTe monolayers can be used as the superior TE materials.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"706 ","pages":"Article 417090"},"PeriodicalIF":2.8,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143591685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This work showcases the influence of single-shot GW correction and spin–orbit coupling (SOC) in accurately determining the quasi-particle (QP) band gap and absorption spectra for bulk and monolayer hexagonal MoS. The computation reveals a QP band gap of bulk 1.34 eV and 2.18 eV for monolayer MoS, respectively. The results were consistent with the experimental findings. The many-body perturbation theory (MBPT) framework was used to investigate electronic and optical properties. The optical properties were investigated using the many-body perturbation theory (MBPT) framework. The findings show consistency between the optical and electronic band gap. Furthermore, it was found that the incorporation of rVV10 nonlocal correlation functional and the range-separated hybrid van der Waals density functional, known as vdW-DF2, improves the structural parameters of the materials with good agreement to experimental measurement. It is also noted that the strong hybridization of s-d orbitals near the Fermi level significantly influences the electronic properties of the MoS. This paper explores the physical properties of MoS, highlighting its potential as a material with a narrow band gap, strong light absorption, and extensive wavelength coverage. The findings demonstrated the suitability of the optimized MoS for next-generation sustainability technologies and highlighted its promise for photodetection applications.
{"title":"Quasi-particle band structure and optical absorption in MoS2: Impact of spin–orbit coupling and vdW corrections for photodetection application","authors":"Shehu Aminu Yamusa , Razif Razali , Amiruddin Shaari , Magaji Ismail , Norah A.M. Alsaif , Najeh Rekik , Ibrahim Isah , Ibtihal M. Alsalamah , S.T. Ahams","doi":"10.1016/j.physb.2025.417074","DOIUrl":"10.1016/j.physb.2025.417074","url":null,"abstract":"<div><div>This work showcases the influence of single-shot G<span><math><msub><mrow></mrow><mrow><mn>0</mn></mrow></msub></math></span>W<span><math><msub><mrow></mrow><mrow><mn>0</mn></mrow></msub></math></span> correction and spin–orbit coupling (SOC) in accurately determining the quasi-particle (QP) band gap and absorption spectra for bulk and monolayer hexagonal MoS<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>. The computation reveals a QP band gap of bulk 1.34 eV and 2.18 eV for monolayer MoS<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, respectively. The results were consistent with the experimental findings. The many-body perturbation theory (MBPT) framework was used to investigate electronic and optical properties. The optical properties were investigated using the many-body perturbation theory (MBPT) framework. The findings show consistency between the optical and electronic band gap. Furthermore, it was found that the incorporation of rVV10 nonlocal correlation functional and the range-separated hybrid van der Waals density functional, known as vdW-DF2, improves the structural parameters of the materials with good agreement to experimental measurement. It is also noted that the strong hybridization of s-d orbitals near the Fermi level significantly influences the electronic properties of the MoS<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>. This paper explores the physical properties of MoS<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, highlighting its potential as a material with a narrow band gap, strong light absorption, and extensive wavelength coverage. The findings demonstrated the suitability of the optimized MoS<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> for next-generation sustainability technologies and highlighted its promise for photodetection applications.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"706 ","pages":"Article 417074"},"PeriodicalIF":2.8,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143601518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The impact of graphene oxide (GO) on the performance of high-temperature superconductors, specifically Bi2223, was examined in this study. Bi2223 samples were produced using a solid-state reaction method with different concentrations of GO. The use of GO, a two-dimensional oxide, resulted in it being a highly effective additive for Bi-based superconductors. Polyvinyl alcohol (PVA) was used to disperse the additive and as a pressing aid. The resulting samples underwent comprehensive characterization using various techniques. The results indicated that adding GO enhanced the superconducting properties of Bi2223, including increases in critical temperature, critical current density, and irreversibility field. Additionally, scanning electron microscopy images demonstrated that GO contributed to improved uniformity of the Bi2223 particles. The study incorporated varying weight percentages of GO (0.1, 0.5, 1, 1.1, and 1.5 wt%) into the Bi2223 precursor powder, with the optimal GO doping level identified as 1 wt%. Overall, this research suggests that GO can be a promising candidate to improve the performance of high-temperature superconductors, particularly Bi2223.
{"title":"Investigation of the effect of varied graphene oxide additions on Bi2223 superconductor properties","authors":"Hossein Koohani , Mardali Yousefpour , Nastaran Riahi Nouri","doi":"10.1016/j.physb.2025.417114","DOIUrl":"10.1016/j.physb.2025.417114","url":null,"abstract":"<div><div>The impact of graphene oxide (GO) on the performance of high-temperature superconductors, specifically Bi2223, was examined in this study. Bi2223 samples were produced using a solid-state reaction method with different concentrations of GO. The use of GO, a two-dimensional oxide, resulted in it being a highly effective additive for Bi-based superconductors. Polyvinyl alcohol (PVA) was used to disperse the additive and as a pressing aid. The resulting samples underwent comprehensive characterization using various techniques. The results indicated that adding GO enhanced the superconducting properties of Bi2223, including increases in critical temperature, critical current density, and irreversibility field. Additionally, scanning electron microscopy images demonstrated that GO contributed to improved uniformity of the Bi2223 particles. The study incorporated varying weight percentages of GO (0.1, 0.5, 1, 1.1, and 1.5 wt%) into the Bi2223 precursor powder, with the optimal GO doping level identified as 1 wt%. Overall, this research suggests that GO can be a promising candidate to improve the performance of high-temperature superconductors, particularly Bi2223.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"706 ","pages":"Article 417114"},"PeriodicalIF":2.8,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143579501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-05DOI: 10.1016/j.physb.2025.417115
Lei Zhang , Xun Ge , Xiaohao Zhou
The theoretical prediction of blue phosphorus has driven research into buckled group-V structures, including arsenic (β-As) and phosphorus (β-P). Inspired by black arsenic-phosphorus, studies on buckled arsenic-phosphorus (β-AsxP1-x) are emerging but remain limited. In this work, we investigate the structural, electronic, and optical properties of monolayer β-AsxP1-x across different arsenic (As) compositions using density functional theory (DFT). By calculating the bandgap values of 1414 structures across 11 compositions, we predict the bowing parameter of the non-linear bandgap-composition relationship. Based on this, one representative structure per composition is selected for further calculations. Our results show that the lattice constants of these structures closely follow Vegard's Law. Monolayer β-AsxP1-x exhibit indirect bandgaps, displaying a non-monotonic trend: initially decreasing and then gradually increasing. Consistent with this trend, the first absorptance peak exhibits a redshift followed by a slight blueshift, with strong near-ultraviolet and moderate visible absorption. These findings demonstrate that β-AsxP1-x compounds exhibit composition-tunable optoelectronic properties, promising for ultraviolet and visible-light electronic devices.
{"title":"First-principles calculations of structural, electronic, and optical properties of monolayer β-AsxP1-x","authors":"Lei Zhang , Xun Ge , Xiaohao Zhou","doi":"10.1016/j.physb.2025.417115","DOIUrl":"10.1016/j.physb.2025.417115","url":null,"abstract":"<div><div>The theoretical prediction of blue phosphorus has driven research into buckled group-V structures, including arsenic (β-As) and phosphorus (β-P). Inspired by black arsenic-phosphorus, studies on buckled arsenic-phosphorus (β-As<sub><em>x</em></sub>P<sub>1-<em>x</em></sub>) are emerging but remain limited. In this work, we investigate the structural, electronic, and optical properties of monolayer β-As<sub><em>x</em></sub>P<sub>1-<em>x</em></sub> across different arsenic (As) compositions using density functional theory (DFT). By calculating the bandgap values of 1414 structures across 11 compositions, we predict the bowing parameter of the non-linear bandgap-composition relationship. Based on this, one representative structure per composition is selected for further calculations. Our results show that the lattice constants of these structures closely follow Vegard's Law. Monolayer β-As<sub><em>x</em></sub>P<sub>1-<em>x</em></sub> exhibit indirect bandgaps, displaying a non-monotonic trend: initially decreasing and then gradually increasing. Consistent with this trend, the first absorptance peak exhibits a redshift followed by a slight blueshift, with strong near-ultraviolet and moderate visible absorption. These findings demonstrate that β-As<sub><em>x</em></sub>P<sub>1-<em>x</em></sub> compounds exhibit composition-tunable optoelectronic properties, promising for ultraviolet and visible-light electronic devices.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"706 ","pages":"Article 417115"},"PeriodicalIF":2.8,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143579503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-03DOI: 10.1016/j.physb.2025.417107
Pan Zhang, Mao Zhao, Longji Luo, Jialu li, Jia Fu, Ning Wang
Two-dimensional (2D) FeOCl materials have garnered significant attention as promising candidates for next-generation thermoelectric (TE) devices. However, achieving dimensionless figure of merit (ZT) in various FeOCl compounds continues to be a major challenge. This paper investigates the TE properties of FeOCl-type materials composed of Sc, Cl, and S, leveraging their structural characteristics and elemental properties. Specifically, the TE performance of 2D FeOCl Sc2Cl2S2 is studied by density function theory and Boltzmann transport theory. The thermodynamic and kinetic stability of 2D Sc2Cl2S2 is confirmed by ab initio molecular dynamics (AIMD) simulations and phonon dispersion curves, revealing a low lattice thermal conductivity (κl) of 0.384 W/mK (0.457 W/mK) along the x (y) axis at 700 K. In addition to meeting the requirements of dynamic and thermodynamic stability, it is necessary to further verify the mechanical stability to indicate the possibility of the stable existence of the structure. To this end, we calculated the mechanical matrix through the perturbation method. The calculation results show that the value of (C11C22-C12C12) is greater than zero, indicating that its mechanical structure is very stable. Finally, the Young's moduli in the x - direction and y - direction were calculated to be 106.28 N/m and 83.26 N/m respectively. Compared with other materials, its stability is good. Furthermore, 2D Sc2Cl2S2 exhibits pronounced anisotropy. Based on n-type doping, the optimal power factor (PF) in x-axis and y-axis is 9.39 mW/mK2 and 21.88 mW/mK2, respectively, demonstrating a 57 % difference. Combining the high PF value and low κl, the highest ZT value at 700 K is found to be 4.21 in the y-axis and 2.55 in the x-axis, with a high anisotropy ratio of 1.65. This study provides a valuable reference for understanding and screening the thermoelectric properties of FeOCl-type materials, and advances the application potential of these materials.
二维（2D）FeOCl 材料作为下一代热电（TE）器件的理想候选材料备受关注。然而，在各种 FeOCl 化合物中实现无量纲优越性（ZT）仍然是一项重大挑战。本文利用由 Sc、Cl 和 S 组成的 FeOCl 型材料的结构特征和元素特性，对其 TE 特性进行了研究。具体来说，本文通过密度函数理论和玻尔兹曼输运理论研究了二维 FeOCl Sc2Cl2S2 的 TE 性能。二维 Sc2Cl2S2 的热力学和动力学稳定性得到了原子分子动力学（ab initio molecular dynamics，AIMD）模拟和声子色散曲线的证实，显示出其在 700 K 时沿 x（y）轴的低晶格热导率（κl）为 0.384 W/mK (0.457 W/mK)。为此，我们通过扰动法计算了力学矩阵。计算结果表明，（C11C22-C12C12）的值大于零，说明其力学结构非常稳定。最后，计算得出 x 方向和 y 方向的杨氏模量分别为 106.28 N/m 和 83.26 N/m。与其他材料相比，其稳定性很好。此外，二维 Sc2Cl2S2 表现出明显的各向异性。在 n 型掺杂的基础上，x 轴和 y 轴的最佳功率因数（PF）分别为 9.39 mW/mK2 和 21.88 mW/mK2，相差 57%。结合高 PF 值和低 κl，700 K 时的最高 ZT 值在 y 轴为 4.21，在 x 轴为 2.55，各向异性比高达 1.65。这项研究为了解和筛选 FeOCl 型材料的热电性能提供了有价值的参考，并推动了这些材料的应用潜力。
{"title":"Two-dimensional Sc2Cl2S2: A promising n-type thermoelectric material with significant anisotropy","authors":"Pan Zhang, Mao Zhao, Longji Luo, Jialu li, Jia Fu, Ning Wang","doi":"10.1016/j.physb.2025.417107","DOIUrl":"10.1016/j.physb.2025.417107","url":null,"abstract":"<div><div>Two-dimensional (2D) FeOCl materials have garnered significant attention as promising candidates for next-generation thermoelectric <em>(</em>TE) devices. However, achieving dimensionless figure of merit (<em>ZT</em>) in various FeOCl compounds continues to be a major challenge. This paper investigates the TE properties of FeOCl-type materials composed of Sc, Cl, and S, leveraging their structural characteristics and elemental properties. Specifically, the TE performance of 2D FeOCl Sc<sub>2</sub>Cl<sub>2</sub>S<sub>2</sub> is studied by density function theory and Boltzmann transport theory. The thermodynamic and kinetic stability of 2D Sc<sub>2</sub>Cl<sub>2</sub>S<sub>2</sub> is confirmed by ab initio molecular dynamics (AIMD) simulations and phonon dispersion curves, revealing a low lattice thermal conductivity (<em>κ</em><sub><em>l</em></sub>) of 0.384 W/mK (0.457 W/mK) along the <em>x</em> (<em>y</em>) axis at 700 K. In addition to meeting the requirements of dynamic and thermodynamic stability, it is necessary to further verify the mechanical stability to indicate the possibility of the stable existence of the structure. To this end, we calculated the mechanical matrix through the perturbation method. The calculation results show that the value of (C<sub>11</sub>C<sub>22</sub>-C<sub>12</sub>C<sub>12</sub>) is greater than zero, indicating that its mechanical structure is very stable. Finally, the Young's moduli in the x - direction and y - direction were calculated to be 106.28 N/m and 83.26 N/m respectively. Compared with other materials, its stability is good. Furthermore, 2D Sc<sub>2</sub>Cl<sub>2</sub>S<sub>2</sub> exhibits pronounced anisotropy. Based on n-type doping, the optimal power factor (<em>PF</em>) in <em>x</em>-axis and <em>y</em>-axis is 9.39 mW/mK<sup>2</sup> and 21.88 mW/mK<sup>2</sup>, respectively, demonstrating a 57 % difference. Combining the high <em>PF</em> value and low <em>κ</em><sub><em>l</em></sub>, the highest <em>ZT</em> value at 700 K is found to be 4.21 in the <em>y</em>-axis and 2.55 in the <em>x</em>-axis, with a high anisotropy ratio of 1.65. This study provides a valuable reference for understanding and screening the thermoelectric properties of FeOCl-type materials, and advances the application potential of these materials.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"706 ","pages":"Article 417107"},"PeriodicalIF":2.8,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143579504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-03DOI: 10.1016/j.physb.2025.417111
Zein K. Heiba , M.M. Ghannam , Mohamed Bakr Mohamed , Hassan Elshimy , Ali Badawi
ZnW1-xInxO4 (x = 0, 0.02, 0.05, 0.07, 0.1) samples were synthesized utilizing the hydrothermal procedure. Synchrotron x-ray diffraction patterns were analyzed applying Rietveld refinement methodology to find out the variation in unit cell parameters, crystallite dimension, atomic positional coordinates, and occupancy values upon doping with different In-concentration (x). Upon doping with In, analysis manifested that both Ni- and W-octahedrons exhibited increased distortion that would engender a polarization moment. Analysis of the measured Raman spectrum confirmed the distortion occurred in the WO6 octahedra by In-doping, where the vibrational modes were shifted or split. The chemical composition and the oxidation states of elements present were investigated using XPS and EDS analyses. The Eg values of the ZnW1-xInxO4 samples are 3.93, 3.9, 3.93, 3.94, and 4.04 eV for x = 0, 0.02, 0.05, 0.07, 0.1 respectively. Photoluminescence (PL) intensity was almost completely quenched upon doping with indium which signifies optimal charge separation conducive to enhanced photocatalytic performance. The current ZnW1-xInxO4 samples were tested as effective catalysts for hydrogen production via sodium borohydride (NaBH4) hydrolysis and methanolysis. Samples with indium content 7% or 5% demonstrated the highest generation rates of 6332 mL min-1g-1 for methanol and 385 mL min-1g-1 for water, respectively. The activation energy (Ea) of the hydrolysis of NaBH4 over ZnW0.95In0.05O4 as a catalyst was determined. The hydrogen production rate increased with increasing temperature. The activated energy was calculated to be 54.87 kJ/mol.
{"title":"Synthesis and physical characterization of ZnW1-xInxO4 nanostructures for hydrogen production","authors":"Zein K. Heiba , M.M. Ghannam , Mohamed Bakr Mohamed , Hassan Elshimy , Ali Badawi","doi":"10.1016/j.physb.2025.417111","DOIUrl":"10.1016/j.physb.2025.417111","url":null,"abstract":"<div><div>ZnW<sub>1-x</sub>In<sub>x</sub>O<sub>4</sub> (x = 0, 0.02, 0.05, 0.07, 0.1) samples were synthesized utilizing the hydrothermal procedure. Synchrotron x-ray diffraction patterns were analyzed applying Rietveld refinement methodology to find out the variation in unit cell parameters, crystallite dimension, atomic positional coordinates, and occupancy values upon doping with different In-concentration (x). Upon doping with In, analysis manifested that both Ni- and W-octahedrons exhibited increased distortion that would engender a polarization moment. Analysis of the measured Raman spectrum confirmed the distortion occurred in the WO<sub>6</sub> octahedra by In-doping, where the vibrational modes were shifted or split. The chemical composition and the oxidation states of elements present were investigated using XPS and EDS analyses. The <em>E</em><sub>g</sub> values of the ZnW<sub>1-x</sub>In<sub>x</sub>O<sub>4</sub> samples are 3.93, 3.9, 3.93, 3.94, and 4.04 eV for x = 0, 0.02, 0.05, 0.07, 0.1 respectively. Photoluminescence (PL) intensity was almost completely quenched upon doping with indium which signifies optimal charge separation conducive to enhanced photocatalytic performance. The current ZnW<sub>1-x</sub>In<sub>x</sub>O<sub>4</sub> samples were tested as effective catalysts for hydrogen production via sodium borohydride (NaBH<sub>4</sub>) hydrolysis and methanolysis. Samples with indium content 7% or 5% demonstrated the highest generation rates of 6332 mL min<sup>-1</sup>g<sup>-1</sup> for methanol and 385 mL min<sup>-1</sup>g<sup>-1</sup> for water, respectively. The activation energy (<em>E</em><sub>a</sub>) of the hydrolysis of NaBH<sub>4</sub> over ZnW<sub>0.95</sub>In<sub>0.05</sub>O<sub>4</sub> as a catalyst was determined. The hydrogen production rate increased with increasing temperature. The activated energy was calculated to be 54.87 kJ/mol.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"706 ","pages":"Article 417111"},"PeriodicalIF":2.8,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143601520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-03DOI: 10.1016/j.physb.2025.417042
Efraem C. Larenio, Ellaine Rose A. Beronio, Alexandra B. Santos-Putungan
The emergence of borophene and its polymorphic phases has opened new possibilities in advanced technologies. Recent experimental studies have demonstrated the potential to synthesize freestanding and phases through methods such as mechanical and liquid phase exfoliation. In this work, we focus on the phase of borophene. Using first-principles calculations, we investigated the properties of borophene monolayers doped with 3d transition metals, namely Cr, Mn, Fe, Co, and Ni. The transition metal (TM) atoms were found to integrate well into the structure, with variations in electronic and magnetic properties depending on the type of impurity atom and its geometric position within the lattice. Cr and Mn doping produced the highest magnetization levels—2.83 and 3.13 , respectively. Notably, the material retained its metallic character even at high concentrations of Cr and Mn atoms. Furthermore, the observed long-range interactions between the impurity atoms in the doubly-doped structures suggest the potential for indirect magnetic spin coupling. These findings offer valuable insights into the properties of 3d TM-doped freestanding borophene, highlighting its potential for applications in spintronics, magnetic storage devices, and other advanced nanotechnologies.
{"title":"Electronic and magnetic properties of freestanding 3d transition metal-doped χ3 borophene: A density functional theory study","authors":"Efraem C. Larenio, Ellaine Rose A. Beronio, Alexandra B. Santos-Putungan","doi":"10.1016/j.physb.2025.417042","DOIUrl":"10.1016/j.physb.2025.417042","url":null,"abstract":"<div><div>The emergence of borophene and its polymorphic phases has opened new possibilities in advanced technologies. Recent experimental studies have demonstrated the potential to synthesize freestanding <span><math><msub><mrow><mi>β</mi></mrow><mrow><mn>12</mn></mrow></msub></math></span> and <span><math><msub><mrow><mi>χ</mi></mrow><mrow><mn>3</mn></mrow></msub></math></span> phases through methods such as mechanical and liquid phase exfoliation. In this work, we focus on the <span><math><msub><mrow><mi>χ</mi></mrow><mrow><mn>3</mn></mrow></msub></math></span> phase of borophene. Using first-principles calculations, we investigated the properties of <span><math><msub><mrow><mi>χ</mi></mrow><mrow><mn>3</mn></mrow></msub></math></span> borophene monolayers doped with 3<em>d</em> transition metals, namely Cr, Mn, Fe, Co, and Ni. The transition metal (TM) atoms were found to integrate well into the <span><math><msub><mrow><mi>χ</mi></mrow><mrow><mn>3</mn></mrow></msub></math></span> structure, with variations in electronic and magnetic properties depending on the type of impurity atom and its geometric position within the lattice. Cr and Mn doping produced the highest magnetization levels—2.83 <span><math><msub><mrow><mi>μ</mi></mrow><mrow><mi>B</mi></mrow></msub></math></span> and 3.13 <span><math><msub><mrow><mi>μ</mi></mrow><mrow><mi>B</mi></mrow></msub></math></span>, respectively. Notably, the material retained its metallic character even at high concentrations of Cr and Mn atoms. Furthermore, the observed long-range interactions between the impurity atoms in the doubly-doped structures suggest the potential for indirect magnetic spin coupling. These findings offer valuable insights into the properties of 3<em>d</em> TM-doped freestanding <span><math><msub><mrow><mi>χ</mi></mrow><mrow><mn>3</mn></mrow></msub></math></span> borophene, highlighting its potential for applications in spintronics, magnetic storage devices, and other advanced nanotechnologies.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"706 ","pages":"Article 417042"},"PeriodicalIF":2.8,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143591684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ZnO oxide is biocompatible and chemically stable material among metal oxides. Zn1-xCuxO thin films have been grown with x = 0.0, 1.0, 2.0 and 3.0 wt% Cu doping through spin coater technique. Films physical properties such as structural, morphology and optical properties are examined via various characterization techniques. X-ray diffractograms of specimen exhibits clear and intense peak at 2θ angle ∼34.5°, refers the hexagonal wurtzite phase. Films vibrational modes are identified using Raman spectroscopy that is centered at 500 and 1050 cm−1 corresponds to pure hexagonal wurtzite phase of ZnO. Pure ZnO film showed high transmittance∼90 %, after introduction of Cu in ZnO matrix, it become reduced. The room temperature photoluminescence spectra is shown near band edge emission peak along with broad visible emission. Films electrical properties and UV Photoresponse shows the significant improvement upon Cu doping in ZnO lattice. Therefore, Cu incorporated ZnO thin films demonstrates high potentiality towards the optoelectronics applications.
{"title":"Improved electrical, UV detection and emission properties of Zn1-xCuxO nano structured thin films for optoelectronics applications","authors":"Ziaul Raza Khan , M. Bouzidi , Mansour Mohamed , Siddhartha","doi":"10.1016/j.physb.2025.417110","DOIUrl":"10.1016/j.physb.2025.417110","url":null,"abstract":"<div><div>ZnO oxide is biocompatible and chemically stable material among metal oxides. Zn<sub>1-x</sub>Cu<sub>x</sub>O thin films have been grown with x = 0.0, 1.0, 2.0 and 3.0 wt% Cu doping through spin coater technique. Films physical properties such as structural, morphology and optical properties are examined via various characterization techniques. X-ray diffractograms of specimen exhibits clear and intense peak at 2θ angle ∼34.5°, refers the hexagonal wurtzite phase. Films vibrational modes are identified using Raman spectroscopy that is centered at 500 and 1050 cm<sup>−1</sup> corresponds to pure hexagonal wurtzite phase of ZnO. Pure ZnO film showed high transmittance∼90 %, after introduction of Cu in ZnO matrix, it become reduced. The room temperature photoluminescence spectra is shown near band edge emission peak along with broad visible emission. Films electrical properties and UV Photoresponse shows the significant improvement upon Cu doping in ZnO lattice. Therefore, Cu incorporated ZnO thin films demonstrates high potentiality towards the optoelectronics applications.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"705 ","pages":"Article 417110"},"PeriodicalIF":2.8,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143549587","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-03DOI: 10.1016/j.physb.2025.417083
Md Mehedi Hasan , Md Amran Sarker , Md Rabbi Talukder , Moshina Binte Mansur , Md Rasidul Islam , Sohail Ahmad
Throughout this investigation, the pressure-driven structural, electronic, optical, and mechanical characteristics of Ge-based lead-free InGeX3 (X = F, Cl) perovskites are inspected. To thoroughly examine these properties under pressure ranging from 0 to 24 GPa for InGeF3 and 0–6 GPa for InGeCl3, where density functional theory (DFT) calculations are performed operating the CASTEP module. Under increasing pressure, the lattice parameter and volumes of unit cells decline, while both compounds reveal thermodynamic stability via formation energy. The band gap of InGeCl3 indicates a direct band gap (R–R) semiconductor of 0.879 eV, whether InGeF3 has an indirect band (R–M) semiconductor of 1.449 eV at ambient pressure utilizing PBE functional. The recalculated band gap for InGeF3 and InGeCl3 are 2.183 eV, and 1.624 eV, respectively utilizing HSE06 functional. Their semiconducting nature changes to a metal with increased pressure. TDOS & PDOS are estimated to understand the origin of the band gap and pressure-induced charge density mapping investigates the bonding characteristics. Under various hydrostatic pressures, the optical properties, among which are the dielectric function, reflectivity, conductivity, refractive index, and absorption coefficient, are calculated and analyzed. These compounds absorb strongly in the UV spectrum, making them ideal for sterilizing surgical instruments, and also absorb well in the visible region, aligning with higher photoconductivity. Besides, their high R values in the high-energy range make them excellent for UV-blocking coatings. However, both compounds have enhanced optoelectronic properties under hydrostatic pressure. Moreover, these perovskites are discovered to remain stable, and ductile within pressure as well as enhanced mechanical characteristics through the elastic constants. Thus, these applicants are highly suitable for solar cells and various optoelectronic devices.
{"title":"Exploring pressure-driven semiconducting to metallic phase transition in lead-free InGeX3 (X=F, Cl) perovskites with tunable optoelectronic and mechanical properties via DFT","authors":"Md Mehedi Hasan , Md Amran Sarker , Md Rabbi Talukder , Moshina Binte Mansur , Md Rasidul Islam , Sohail Ahmad","doi":"10.1016/j.physb.2025.417083","DOIUrl":"10.1016/j.physb.2025.417083","url":null,"abstract":"<div><div>Throughout this investigation, the pressure-driven structural, electronic, optical, and mechanical characteristics of Ge-based lead-free InGeX<sub>3</sub> (X = F, Cl) perovskites are inspected. To thoroughly examine these properties under pressure ranging from 0 to 24 GPa for InGeF<sub>3</sub> and 0–6 GPa for InGeCl<sub>3</sub>, where density functional theory (DFT) calculations are performed operating the CASTEP module. Under increasing pressure, the lattice parameter and volumes of unit cells decline, while both compounds reveal thermodynamic stability via formation energy. The band gap of InGeCl<sub>3</sub> indicates a direct band gap (R–R) semiconductor of 0.879 eV, whether InGeF<sub>3</sub> has an indirect band (R–M) semiconductor of 1.449 eV at ambient pressure utilizing PBE functional. The recalculated band gap for InGeF<sub>3</sub> and InGeCl<sub>3</sub> are 2.183 eV, and 1.624 eV, respectively utilizing HSE06 functional. Their semiconducting nature changes to a metal with increased pressure. TDOS & PDOS are estimated to understand the origin of the band gap and pressure-induced charge density mapping investigates the bonding characteristics. Under various hydrostatic pressures, the optical properties, among which are the dielectric function, reflectivity, conductivity, refractive index, and absorption coefficient, are calculated and analyzed. These compounds absorb strongly in the UV spectrum, making them ideal for sterilizing surgical instruments, and also absorb well in the visible region, aligning with higher photoconductivity. Besides, their high R values in the high-energy range make them excellent for UV-blocking coatings. However, both compounds have enhanced optoelectronic properties under hydrostatic pressure. Moreover, these perovskites are discovered to remain stable, and ductile within pressure as well as enhanced mechanical characteristics through the elastic constants. Thus, these applicants are highly suitable for solar cells and various optoelectronic devices.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"705 ","pages":"Article 417083"},"PeriodicalIF":2.8,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143549896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-03DOI: 10.1016/j.physb.2025.417109
Haixu Wang , Qixin Li , Liangbi Su , Huamin Kou , A.M. Kalashnikova , Anhua Wu
Rare-earth orthoferrites have attracted widespread attention in recent years due to their rich physical properties. In this study, high-quality Er0.6Gd0.4FeO3 (EGFO64) single crystals were grown using the optical floating zone method, and their magnetic properties were investigated. A novel secondary spin reorientation transition is reported, which occurs from Γ4(GxAyFz) to Γ3(CxFyAz) and back to Γ4(GxAyFz), exhibiting a significant nonzero spontaneous magnetization along the b-axis. This phenomenon is rare in most RFeO3 compounds. Additionally, an incomplete spin flip with magnetic field dependence was observed along the b-axis, which can be attributed to the changes in the arrangement of Er3+, Gd3+, and Fe3+ ions. Furthermore, the results of the spin reorientation transition under different magnetic fields indicate that the magnetic field can control the anisotropic interactions between the R3+ and Fe3+ ions. These characteristics of the EGFO64 single crystal contribute to the understanding of the influence of rare-earth doping on the magnetic structure and physical phenomena in RFeO3, and the crystal shows great potential for applications in magnetization switching, ultrafast magneto-optical recording, and other related fields.
{"title":"Continuous two spin reorientation transitions and spin flips along the b-axis in Er0.6Gd0.4FeO3 single crystal","authors":"Haixu Wang , Qixin Li , Liangbi Su , Huamin Kou , A.M. Kalashnikova , Anhua Wu","doi":"10.1016/j.physb.2025.417109","DOIUrl":"10.1016/j.physb.2025.417109","url":null,"abstract":"<div><div>Rare-earth orthoferrites have attracted widespread attention in recent years due to their rich physical properties. In this study, high-quality Er<sub>0</sub>.<sub>6</sub>Gd<sub>0</sub>.<sub>4</sub>FeO<sub>3</sub> (EGFO64) single crystals were grown using the optical floating zone method, and their magnetic properties were investigated. A novel secondary spin reorientation transition is reported, which occurs from Γ<sub>4</sub>(G<sub>x</sub>A<sub>y</sub>F<sub>z</sub>) to Γ<sub>3</sub>(C<sub>x</sub>F<sub>y</sub>A<sub>z</sub>) and back to Γ<sub>4</sub>(G<sub>x</sub>A<sub>y</sub>F<sub>z</sub>), exhibiting a significant nonzero spontaneous magnetization along the b-axis. This phenomenon is rare in most RFeO<sub>3</sub> compounds. Additionally, an incomplete spin flip with magnetic field dependence was observed along the b-axis, which can be attributed to the changes in the arrangement of Er<sup>3+</sup>, Gd<sup>3+</sup>, and Fe<sup>3+</sup> ions. Furthermore, the results of the spin reorientation transition under different magnetic fields indicate that the magnetic field can control the anisotropic interactions between the R<sup>3+</sup> and Fe<sup>3+</sup> ions. These characteristics of the EGFO64 single crystal contribute to the understanding of the influence of rare-earth doping on the magnetic structure and physical phenomena in RFeO<sub>3</sub>, and the crystal shows great potential for applications in magnetization switching, ultrafast magneto-optical recording, and other related fields.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"705 ","pages":"Article 417109"},"PeriodicalIF":2.8,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143549585","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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