Pub Date : 2025-10-23DOI: 10.1016/j.physe.2025.116395
Tran Cong Phong , Ta T. Tho , Le T.T. Phuong
We investigate the topological properties of monolayer jacutingaite PtHgSe by analyzing its thermal and magnetic responses under static and dynamic electric fields. In doing so, we use the Kane–Mele model and the semiclassical Boltzmann approach. Through semiclassical calculations, we demonstrate how topological phase transitions induced by these fields are reflected in the material’s electronic heat capacity and Pauli spin susceptibility. We find that in the semimetallic phase, the low-temperature regime exhibits the highest magnitudes of these properties. In contrast, the responses are weaker and stronger for the band insulator and quantum Hall insulator phases, respectively, than the pristine quantum spin Hall insulator phase. This work offers a pathway for detecting topological features in the thermal and magnetic properties of materials.
{"title":"Detecting topological phase transition in monolayer jacutingaite Pt2HgSe3 via thermal and magnetic properties","authors":"Tran Cong Phong , Ta T. Tho , Le T.T. Phuong","doi":"10.1016/j.physe.2025.116395","DOIUrl":"10.1016/j.physe.2025.116395","url":null,"abstract":"<div><div>We investigate the topological properties of monolayer jacutingaite Pt<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>HgSe<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> by analyzing its thermal and magnetic responses under static and dynamic electric fields. In doing so, we use the Kane–Mele model and the semiclassical Boltzmann approach. Through semiclassical calculations, we demonstrate how topological phase transitions induced by these fields are reflected in the material’s electronic heat capacity and Pauli spin susceptibility. We find that in the semimetallic phase, the low-temperature regime exhibits the highest magnitudes of these properties. In contrast, the responses are weaker and stronger for the band insulator and quantum Hall insulator phases, respectively, than the pristine quantum spin Hall insulator phase. This work offers a pathway for detecting topological features in the thermal and magnetic properties of materials.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"175 ","pages":"Article 116395"},"PeriodicalIF":2.9,"publicationDate":"2025-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145363367","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 : 2025-10-23DOI: 10.1016/j.physe.2025.116398
G.P. Fuentes , L.A.P. Gonçalves , E. Padrón-Hernández , M. Cabrera-Baez
We present a quantitative micromagnetic study on spin wave dynamics in sinusoidally undulated YIG nanostrip, demonstrating that surface geometry can induce magnonic branch-enlargement without compositional modulation. Our simulations reveal that for surface modes (), increasing of ripple depth from 5 nm to 20 nm results in a band broadening scaling linearly from 0.5 GHz to 2.0 GHz. For Volume modes () forbidden band gaps appear from wave-vectors (rad/nm). We propose an analytical scaling , validated by the numerical data, establishing a predictive model for ripple-induced spectral modulation. The curvature-driven anisotropy and demagnetizing field variations explain the observed spectral diffusion. Our results provide a robust framework for geometrical control of spin wave propagation, offering a design pathway for planar, lithography-compatible magnonic devices with reconfigurable dispersion characteristics. At this level, annalistic calculations are not efficient.
{"title":"Geometry-driven modulation of spin wave spectra in undulated YIG nanostrip","authors":"G.P. Fuentes , L.A.P. Gonçalves , E. Padrón-Hernández , M. Cabrera-Baez","doi":"10.1016/j.physe.2025.116398","DOIUrl":"10.1016/j.physe.2025.116398","url":null,"abstract":"<div><div>We present a quantitative micromagnetic study on spin wave dynamics in sinusoidally undulated YIG nanostrip, demonstrating that surface geometry can induce magnonic branch-enlargement without compositional modulation. Our simulations reveal that for surface modes (<span><math><mrow><mover><mrow><mi>k</mi></mrow><mo>→</mo></mover><mo>⊥</mo><msub><mrow><mover><mrow><mi>H</mi></mrow><mo>→</mo></mover></mrow><mrow><mn>0</mn></mrow></msub></mrow></math></span>), increasing of ripple depth <span><math><mi>δ</mi></math></span> from 5 nm to 20 nm results in a band broadening <span><math><mrow><mi>Δ</mi><mi>f</mi></mrow></math></span> scaling linearly from 0.5 GHz to 2.0 GHz. For Volume modes (<span><math><mrow><mover><mrow><mi>k</mi></mrow><mo>→</mo></mover><mo>∥</mo><msub><mrow><mover><mrow><mi>H</mi></mrow><mo>→</mo></mover></mrow><mrow><mn>0</mn></mrow></msub></mrow></math></span>) forbidden band gaps appear from wave-vectors <span><math><mrow><mi>k</mi><mo>=</mo><mi>m</mi><mi>π</mi><mo>/</mo><msub><mrow><mi>λ</mi></mrow><mrow><mi>N</mi></mrow></msub><mo>≈</mo><mn>0</mn><mo>.</mo><mn>1</mn></mrow></math></span> (rad/nm). We propose an analytical scaling <span><math><mrow><mi>Δ</mi><mi>f</mi><mo>∝</mo><mi>δ</mi><msup><mrow><mo>sin</mo></mrow><mrow><mn>2</mn></mrow></msup><mrow><mo>(</mo><mi>π</mi><mi>k</mi><mo>/</mo><msub><mrow><mi>k</mi></mrow><mrow><mi>Bragg</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span>, validated by the numerical data, establishing a predictive model for ripple-induced spectral modulation. The curvature-driven anisotropy and demagnetizing field variations explain the observed spectral diffusion. Our results provide a robust framework for geometrical control of spin wave propagation, offering a design pathway for planar, lithography-compatible magnonic devices with reconfigurable dispersion characteristics. At this level, annalistic calculations are not efficient.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"175 ","pages":"Article 116398"},"PeriodicalIF":2.9,"publicationDate":"2025-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145363366","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 : 2025-10-23DOI: 10.1016/j.physe.2025.116392
Muhammad Hasnain Jameel , Samreen Kousar , Aqeela Yaseen , Jia Luo , Hongyan Wang
The structure, electronic, optical, and thermal properties of monolayer zirconium trihalides ZrX3 (X = Cl, Br, I) have been studied by density functional theory. The calculation of optical constants confirms that ZrCl3, ZrBr3, and ZrI3 have strong optical anisotropy. In the visible range, the light absorption efficiency of ZrCl3, ZrBr3, and ZrI3 is measured in the direction of the electric field. More interestingly, the optical absorption coefficient within ultraviolet and visible infrared regions is , and for ZrCl3, ZrBr3 and ZrI3 respectively. The absorption edge systematically red shifts from ZrCl3, ZrBr3, and ZrI3, reflecting the reduction in energy bandgap (Eg) from 2.46, 1.90, to 0.42 eV with heavier halogen atoms Cl, Br, and I, respectively. The thermal impact on macroscopic properties of ZrCl3, ZrBr3, and ZrI3 is predicted using the quasi-harmonic Debye model. According to Mesodynamics analysis, monolayer zirconium trihalide ZrX3 (X = Cl, Br, I) shows mass and bonding heterogeneity, decreases light scattering, and increases thermal conductivity, as indicated by red color high potential regions and blue color low potential and middle color shows variation in density may be due to atomic/mass density defect. Phonon dispersion explored at the mesoscale level shows that at lower frequency, optical modes of ZrCl3, ZrBr3, and ZrI3 couple more strongly with acoustic modes, increasing phonon-phonon scattering and increasing thermal conductivity. The variations of the enthalpy (U-U), entropy (S-S), heat capacity, Debye temperature, and free energy with temperature function are obtained successfully. It is astounding that ZrCl3 shows prominent thermal stability as compared to ZrBr3 and ZrI3 at high temperatures, such as above 150 K.
{"title":"First-principles calculations of structural, optoelectronic, and thermal behavior of 2D monolayer zirconium trihalide ZrX3 (X =Cl, Br, I) for photocatalytic application","authors":"Muhammad Hasnain Jameel , Samreen Kousar , Aqeela Yaseen , Jia Luo , Hongyan Wang","doi":"10.1016/j.physe.2025.116392","DOIUrl":"10.1016/j.physe.2025.116392","url":null,"abstract":"<div><div>The structure, electronic, optical, and thermal properties of monolayer zirconium trihalides ZrX<sub>3</sub> (X = Cl, Br, I) have been studied by density functional theory. The calculation of optical constants confirms that ZrCl<sub>3</sub>, ZrBr<sub>3,</sub> and ZrI<sub>3</sub> have strong optical anisotropy. In the visible range, the light absorption efficiency of ZrCl<sub>3</sub>, ZrBr<sub>3,</sub> and ZrI<sub>3</sub> is measured in the direction of the electric field. More interestingly, the optical absorption coefficient within ultraviolet and visible infrared regions is <span><math><mrow><mn>3</mn><mo>×</mo><msup><mn>10</mn><mn>5</mn></msup><mspace></mspace><msup><mrow><mi>c</mi><mi>m</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span>, <span><math><mrow><mn>1.9</mn><mo>×</mo><msup><mn>10</mn><mn>5</mn></msup><mspace></mspace><msup><mrow><mi>c</mi><mi>m</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span> and <span><math><mrow><mn>1.8</mn><mo>×</mo><msup><mn>10</mn><mn>5</mn></msup><mspace></mspace><msup><mrow><mi>c</mi><mi>m</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span> for ZrCl<sub>3</sub>, ZrBr<sub>3</sub> and ZrI<sub>3</sub> respectively. The absorption edge systematically red shifts from ZrCl<sub>3</sub>, ZrBr<sub>3,</sub> and ZrI<sub>3</sub>, reflecting the reduction in energy bandgap (E<sub>g</sub>) from 2.46, 1.90, to 0.42 eV with heavier halogen atoms Cl, Br, and I, respectively. The thermal impact on macroscopic properties of ZrCl<sub>3</sub>, ZrBr<sub>3,</sub> and ZrI<sub>3</sub> is predicted using the quasi-harmonic Debye model. According to Mesodynamics analysis, monolayer zirconium trihalide ZrX<sub>3</sub> (X = Cl, Br, I) shows mass and bonding heterogeneity, decreases light scattering, and increases thermal conductivity, as indicated by red color high potential regions and blue color low potential and middle color shows variation in density may be due to atomic/mass density defect. Phonon dispersion explored at the mesoscale level shows that at lower frequency, optical modes of ZrCl<sub>3</sub>, ZrBr<sub>3,</sub> and ZrI<sub>3</sub> couple more strongly with acoustic modes, increasing phonon-phonon scattering and increasing thermal conductivity. The variations of the enthalpy (U-U), entropy (S-S), heat capacity, Debye temperature, and free energy with temperature function are obtained successfully. It is astounding that ZrCl<sub>3</sub> shows prominent thermal stability as compared to ZrBr<sub>3</sub> and ZrI<sub>3</sub> at high temperatures, such as above 150 K.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"175 ","pages":"Article 116392"},"PeriodicalIF":2.9,"publicationDate":"2025-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145417027","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 : 2025-10-21DOI: 10.1016/j.physe.2025.116393
H. Vargová
We rigorously analyse global tripartite entanglement in a mixed-spin (,,) Heisenberg trimer under varying exchange couplings, magnetic fields, and temperatures. Entanglement is quantified using the geometric mean of all three bipartite negativities, enabling us to map precisely the regions of spontaneous global entanglement and to classify the tripartite states according to the distribution of reduced bipartite correlations. We further investigate the thermal stability of entanglement across the full parameter space, with particular focus on the experimentally realised trimer [Ni(bapa)(HO)]Cu(pba)(ClO) (bapa = bis(3-aminopropyl)amine; pba = 1, 3-propylenebis(oxamato)), where global entanglement is predicted to persist up to K and magnetic fields approaching 210 T. Notably, we observe a thermally induced activation of robust entanglement in regions with a biseparable ground state, reaching values close to - a phenomenon not previously reported. Finally, we propose a connection between the theoretically predicted tripartite entanglement and experimentally measurable quantities.
{"title":"Robust global tripartite entanglement in a mixed spin-(1,1/2,1) Heisenberg trimer","authors":"H. Vargová","doi":"10.1016/j.physe.2025.116393","DOIUrl":"10.1016/j.physe.2025.116393","url":null,"abstract":"<div><div>We rigorously analyse global tripartite entanglement in a mixed-spin (<span><math><mn>1</mn></math></span>,<span><math><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></math></span>,<span><math><mn>1</mn></math></span>) Heisenberg trimer under varying exchange couplings, magnetic fields, and temperatures. Entanglement is quantified using the geometric mean of all three bipartite negativities, enabling us to map precisely the regions of spontaneous global entanglement and to classify the tripartite states according to the distribution of reduced bipartite correlations. We further investigate the thermal stability of entanglement across the full parameter space, with particular focus on the experimentally realised trimer [Ni(bapa)(H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>O)]<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Cu(pba)(ClO<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span>)<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> (bapa = bis(3-aminopropyl)amine; pba = 1, 3-propylenebis(oxamato)), where global entanglement is predicted to persist up to <span><math><mrow><mo>∼</mo><mn>100</mn></mrow></math></span> K and magnetic fields approaching 210 T. Notably, we observe a thermally induced activation of robust entanglement in regions with a biseparable ground state, reaching values close to <span><math><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></math></span> - a phenomenon not previously reported. Finally, we propose a connection between the theoretically predicted tripartite entanglement and experimentally measurable quantities.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"175 ","pages":"Article 116393"},"PeriodicalIF":2.9,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145363433","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 : 2025-10-19DOI: 10.1016/j.physe.2025.116390
Mohammed Khalis , Abdennabi Morchid , Rachid Masrour
In this work, we conducted a study aimed at analyzing the impact of uniform electric and magnetic fields on the behavior of charge carriers in a solar cell, with particular focus on the evolution of the photocurrent. Relying on the classical laws of electrodynamics, formulated within a covariant framework, we established the fundamental relationship between the electric field and the magnetic field through the Lorentz force, without initially accounting for collisional interactions. The equations of motion of electrons and holes—describing in particular the cycloidal trajectories of carriers and the drift velocity resulting from the combined action of the two fields—constitute the theoretical basis of our analysis. The application of this formalism to the operation of a solar cell subjected to a perpendicular magnetic field reveals distinct behaviors depending on the region considered. In the depletion region, where the internal electric field is strong, the influence of the magnetic field is significant and markedly alters carrier trajectories. In contrast, in the neutral regions dominated by diffusive transport, its effect remains negligible. The results confirm that increasing the magnetic field intensity leads to a substantial reduction in the photocurrent. For instance, in a silicon solar cell with a surface area of 100 cm2 under illumination at 25 °C, MATLAB simulations indicate a decrease in photocurrent from 3.6 A to 2.6 A as the magnetic field increases from 0 to 50 mT. Experimentally, the study of a photovoltaic module with a surface area of 270 cm2 under illumination shows a reduction in photocurrent from 205 to 90 mA, accompanied by an increase in series resistance from 7.76 to 17.70 Ω, under the same magnetic field variation. When the effect of collisional forces is subsequently incorporated into the modeling, the influence of the magnetic field on both series resistance and photocurrent reduction becomes even more pronounced. These findings highlight an excellent agreement between the modeling—which simultaneously accounts for electrical, magnetic, and collisional contributions—and the experimental observations, thereby validating the relevance of the proposed model and its ability to faithfully describe the behavior of solar cells in the presence of a magnetic field.
{"title":"Impact of magnetic field on photocurrent: A classical electrodynamic study, simulation, and experimental validation","authors":"Mohammed Khalis , Abdennabi Morchid , Rachid Masrour","doi":"10.1016/j.physe.2025.116390","DOIUrl":"10.1016/j.physe.2025.116390","url":null,"abstract":"<div><div>In this work, we conducted a study aimed at analyzing the impact of uniform electric and magnetic fields on the behavior of charge carriers in a solar cell, with particular focus on the evolution of the photocurrent. Relying on the classical laws of electrodynamics, formulated within a covariant framework, we established the fundamental relationship between the electric field <span><math><mrow><mover><mi>E</mi><mo>→</mo></mover></mrow></math></span> and the magnetic field <span><math><mrow><mover><mi>B</mi><mo>→</mo></mover></mrow></math></span> through the Lorentz force, without initially accounting for collisional interactions. The equations of motion of electrons and holes—describing in particular the cycloidal trajectories of carriers and the drift velocity resulting from the combined action of the two fields—constitute the theoretical basis of our analysis. The application of this formalism to the operation of a solar cell subjected to a perpendicular magnetic field reveals distinct behaviors depending on the region considered. In the depletion region, where the internal electric field is strong, the influence of the magnetic field is significant and markedly alters carrier trajectories. In contrast, in the neutral regions dominated by diffusive transport, its effect remains negligible. The results confirm that increasing the magnetic field intensity leads to a substantial reduction in the photocurrent. For instance, in a silicon solar cell with a surface area of 100 cm<sup>2</sup> under <span><math><mrow><mn>1000</mn><mspace></mspace><mi>W</mi><mo>.</mo><msup><mi>m</mi><mrow><mo>−</mo><mn>2</mn></mrow></msup></mrow></math></span> illumination at 25 °C, MATLAB simulations indicate a decrease in photocurrent from 3.6 A to 2.6 A as the magnetic field increases from 0 to 50 mT. Experimentally, the study of a photovoltaic module with a surface area of 270 cm<sup>2</sup> under <span><math><mrow><mn>600</mn><mspace></mspace><mi>W</mi><mo>.</mo><msup><mi>m</mi><mrow><mo>−</mo><mn>2</mn></mrow></msup></mrow></math></span> illumination shows a reduction in photocurrent from 205 to 90 mA, accompanied by an increase in series resistance from 7.76 to 17.70 Ω, under the same magnetic field variation. When the effect of collisional forces is subsequently incorporated into the modeling, the influence of the magnetic field on both series resistance and photocurrent reduction becomes even more pronounced. These findings highlight an excellent agreement between the modeling—which simultaneously accounts for electrical, magnetic, and collisional contributions—and the experimental observations, thereby validating the relevance of the proposed model and its ability to faithfully describe the behavior of solar cells in the presence of a magnetic field.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"175 ","pages":"Article 116390"},"PeriodicalIF":2.9,"publicationDate":"2025-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145363310","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 : 2025-10-15DOI: 10.1016/j.physe.2025.116388
Bratati Mukhopadhyay, P.K. Basu
Direct bandgap Ge1-xSnx (x > 0.08) alloys have emerged as highly promising materials for next-generation high-speed electronic, thermoelectric, and photonic devices, owing to their tunable band structure and compatibility with standard CMOS technology on silicon platforms. The transition from indirect to direct band gap for Sn concentration exceeding 8 % has made these alloys attractive for photonic applications such as mid-infrared lasers, modulators, and photodetectors, particularly in the 2–5 μm wavelength range. An earlier study predicted that the electron mobility in the non-degenerate Ge1-xSnx alloy would increase by 50 times for x ≥ 0.08 from the value in pure Ge (3900 cm2/V-sec) due to increased separation between Γ and L valleys and consequent reduction in intervalley scattering. In the present work, a realistic theoretical estimate is made of mobility of bulk Ge1-xSnx under both non-degenerate and degenerate condition for a wide range of Sn concentration (0 < x < 0.2) covering indirect and direct bandgap nature of the alloy. The theoretical values of mobility show excellent agreement with the experimental values reported for x = 0.02, and satisfactory agreement for x = 0.125. For the calculation of mobility, scattering by phonons (deformation potential acoustic, optical and intervalley), alloy-disorder, impurity as well as electron-electron scattering have been taken into consideration.
{"title":"Analytical modeling of electron mobility in non-degenerate and degenerate bulk n-Ge1-xSnx","authors":"Bratati Mukhopadhyay, P.K. Basu","doi":"10.1016/j.physe.2025.116388","DOIUrl":"10.1016/j.physe.2025.116388","url":null,"abstract":"<div><div>Direct bandgap Ge<sub>1-x</sub>Sn<sub>x</sub> (x > 0.08) alloys have emerged as highly promising materials for next-generation high-speed electronic, thermoelectric, and photonic devices, owing to their tunable band structure and compatibility with standard CMOS technology on silicon platforms. The transition from indirect to direct band gap for Sn concentration exceeding 8 % has made these alloys attractive for photonic applications such as mid-infrared lasers, modulators, and photodetectors, particularly in the 2–5 μm wavelength range. An earlier study predicted that the electron mobility in the non-degenerate Ge<sub>1-x</sub>Sn<sub>x</sub> alloy would increase by 50 times for x ≥ 0.08 from the value in pure Ge (3900 cm<sup>2</sup>/V-sec) due to increased separation between Γ and L valleys and consequent reduction in intervalley scattering. In the present work, a realistic theoretical estimate is made of mobility of bulk Ge<sub>1-x</sub>Sn<sub>x</sub> under both non-degenerate and degenerate condition for a wide range of Sn concentration (0 < x < 0.2) covering indirect and direct bandgap nature of the alloy. The theoretical values of mobility show excellent agreement with the experimental values reported for x = 0.02, and satisfactory agreement for x = 0.125. For the calculation of mobility, scattering by phonons (deformation potential acoustic, optical and intervalley), alloy-disorder, impurity as well as electron-electron scattering have been taken into consideration.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"175 ","pages":"Article 116388"},"PeriodicalIF":2.9,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145324746","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}
Two-dimensional (2D) materials have emerged as a prominent research focus due to their excellent properties and broad application. Among these, tungsten diselenide (WSe2), a representative transition-metal dichalcogenide (TMDC), exhibits high carrier mobility and a tunable band gap when reduced to a 2D structure, making it particularly attractive for electronic and optoelectronic applications. However, the inherent weak absorption in 2D materials remains a fundamental limitation. To address this challenge, we developed a heterojunction photodetector by integrating Ag-In-Ga-S (AIGS) quantum dots (QDs) with 2D WSe2. The device combines the superior high carrier mobility of 2D materials with the strong light-harvesting capability of quantum dots, facilitating efficient photogenerated carrier separation and enhanced photocurrents, thereby improving photoresponse performance. The obtained heterojunction demonstrates extraordinary optoelectronic performance, achieving a responsivity of 1.81 × 104 A/W, a detectivity of 1.3 × 1013 Jones and an external quantum efficiency of 4.27 × 105 %. These results indicate the significant potential of 2D materials/QDs hybrid systems for advanced photodetector applications.
{"title":"High-performance photodetector based on hybrid 2D WSe2/Ag-in-Ga-S QDs heterojunction","authors":"Jiahao Yang, Banqin Ruan, Zhentao Ke, Jiahao Zhang, Yiyang An, Zixuan Guo, Zhi Li, Xiufeng Song, Haibo Zeng","doi":"10.1016/j.physe.2025.116391","DOIUrl":"10.1016/j.physe.2025.116391","url":null,"abstract":"<div><div>Two-dimensional (2D) materials have emerged as a prominent research focus due to their excellent properties and broad application. Among these, tungsten diselenide (WSe<sub>2</sub>), a representative transition-metal dichalcogenide (TMDC), exhibits high carrier mobility and a tunable band gap when reduced to a 2D structure, making it particularly attractive for electronic and optoelectronic applications. However, the inherent weak absorption in 2D materials remains a fundamental limitation. To address this challenge, we developed a heterojunction photodetector by integrating Ag-In-Ga-S (AIGS) quantum dots (QDs) with 2D WSe<sub>2</sub>. The device combines the superior high carrier mobility of 2D materials with the strong light-harvesting capability of quantum dots, facilitating efficient photogenerated carrier separation and enhanced photocurrents, thereby improving photoresponse performance. The obtained heterojunction demonstrates extraordinary optoelectronic performance, achieving a responsivity of 1.81 × 10<sup>4</sup> A/W, a detectivity of 1.3 × 10<sup>13</sup> Jones and an external quantum efficiency of 4.27 × 10<sup>5</sup> %. These results indicate the significant potential of 2D materials/QDs hybrid systems for advanced photodetector applications.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"175 ","pages":"Article 116391"},"PeriodicalIF":2.9,"publicationDate":"2025-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145324745","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 : 2025-10-10DOI: 10.1016/j.physe.2025.116389
Wen-Zhi Xiao, Gang Xiao, Hai-Qing Xu, Xin-Hua Gao, Jun He
Two-dimensional (2D) multifunctional materials with distinctive features such as magnetic, ferroelectric, piezoelectric, and optical property are in high demand due to their potential applications in novel nanoscale devices. Herein, based on first-principles calculations, we present a family of 2D multiferroic MoNX2 (X = F, Cl, Br, I) materials. Among them, MoNF2 is an anti-ferroelectric (AFE) ferromagnetic (FM) semiconductor with Curie temperature (TC) of 497 K. MoNX2 (X = Cl, Br) are ferroelectric (FE) antiferromagnetic (AFM) semiconductors. All of them exhibit an in-plane spontaneous electric polarization of up to 260 pC m−1 and piezoelectric response. The FE switching energy barrier is no more than 0.1 eV per atom for them. Additionally, they exhibit strong linear optical dichroism and hyperbolicity in the visible light region. The alignments of the band edges of MoNX2 (X = Cl, Br, I) with the redox potentials of water show that these materials are suitable for use as photocatalysts for water splitting. Their intriguing magnetic, electronic, ferroelectric, piezoelectric and optical properties render them ideal for use in high-performance, multifunctional applications.
{"title":"Two-dimensional high-temperature magnetic MoNX2 (X = F, Cl, Br, I) with piezoelectricity, ferroelectricity, and optical anisotropy","authors":"Wen-Zhi Xiao, Gang Xiao, Hai-Qing Xu, Xin-Hua Gao, Jun He","doi":"10.1016/j.physe.2025.116389","DOIUrl":"10.1016/j.physe.2025.116389","url":null,"abstract":"<div><div>Two-dimensional (2D) multifunctional materials with distinctive features such as magnetic, ferroelectric, piezoelectric, and optical property are in high demand due to their potential applications in novel nanoscale devices. Herein, based on first-principles calculations, we present a family of 2D multiferroic MoNX<sub>2</sub> (X = F, Cl, Br, I) materials. Among them, MoNF<sub>2</sub> is an anti-ferroelectric (AFE) ferromagnetic (FM) semiconductor with Curie temperature (T<sub>C</sub>) of 497 K. MoNX<sub>2</sub> (X = Cl, Br) are ferroelectric (FE) antiferromagnetic (AFM) semiconductors. All of them exhibit an in-plane spontaneous electric polarization of up to 260 pC m<sup>−1</sup> and piezoelectric response. The FE switching energy barrier is no more than 0.1 eV per atom for them. Additionally, they exhibit strong linear optical dichroism and hyperbolicity in the visible light region. The alignments of the band edges of MoNX<sub>2</sub> (X = Cl, Br, I) with the redox potentials of water show that these materials are suitable for use as photocatalysts for water splitting. Their intriguing magnetic, electronic, ferroelectric, piezoelectric and optical properties render them ideal for use in high-performance, multifunctional applications.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"175 ","pages":"Article 116389"},"PeriodicalIF":2.9,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145324744","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 : 2025-10-09DOI: 10.1016/j.physe.2025.116387
Lan Luo , Xianjuan He , Wenzhe Zhou , Qinglin Xia , Fangping Ouyang
Due to the role of the valley as an information carriers, two-dimensional valleytronics materials have broad prospects in information storage in the future. However, materials with intrinsic valley polarization are rare. In our work, using first-principles calculations, we propose a valleytronics material monolayer (ML) AgMoP2S6 with a ferromagnetic(FM) ground state. The ferromagnetic exchange interaction breaks the time-reversal symmetry, which results in a spontaneous valley polarization of 78 meV at the K/-K points on the valence band under the action of strong SOC. The valley polarization can be tuned by biaxial strain and Hubbard U, and when the tensile strain exceeds 4 % and U exceeds 2 eV, valley polarization also appears in the conduction band. Under the action of an in-plane electric field, the breaking of valley degeneracy makes the appearance of anomalous valley Hall effect (AVHE) effect a possibility. ML AgMoP2S6 is an ideal valleytronics material.
{"title":"Manipulation of valley polarization and anomalous valley Hall effect in monolayer ferrovalley AgMoP2S6","authors":"Lan Luo , Xianjuan He , Wenzhe Zhou , Qinglin Xia , Fangping Ouyang","doi":"10.1016/j.physe.2025.116387","DOIUrl":"10.1016/j.physe.2025.116387","url":null,"abstract":"<div><div>Due to the role of the valley as an information carriers, two-dimensional valleytronics materials have broad prospects in information storage in the future. However, materials with intrinsic valley polarization are rare. In our work, using first-principles calculations, we propose a valleytronics material monolayer (ML) AgMoP<sub>2</sub>S<sub>6</sub> with a ferromagnetic(FM) ground state. The ferromagnetic exchange interaction breaks the time-reversal symmetry, which results in a spontaneous valley polarization of 78 meV at the K/-K points on the valence band under the action of strong SOC. The valley polarization can be tuned by biaxial strain and Hubbard U, and when the tensile strain exceeds 4 % and U exceeds 2 eV, valley polarization also appears in the conduction band. Under the action of an in-plane electric field, the breaking of valley degeneracy makes the appearance of anomalous valley Hall effect (AVHE) effect a possibility. ML AgMoP<sub>2</sub>S<sub>6</sub> is an ideal valleytronics material.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"175 ","pages":"Article 116387"},"PeriodicalIF":2.9,"publicationDate":"2025-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145267669","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 : 2025-10-09DOI: 10.1016/j.physe.2025.116385
Pengbin Niu , Li Xu , Hui Yao , Hong-Gang Luo
We investigate the thermoelectrical transport in a system of non-Hermitian double quantum dots. For that purpose, we set up a model where two quantum dots are experiencing gain and loss of energy and in proximity to two superconductors. By applying Keldysh Green’s function technique, we study the transmission function, conductance as well as the Seebeck coefficient. We calculate the thermoelectric quantities both analytically and numerically and show that a sign change of the Seebeck coefficient can occur when electrons transport through the Andreev bound states forming on the quantum dots. The sign change is induced by the competition of superconducting pairing potential and PT-symmetric complex potential, when the system passes through the exceptional point. These findings may be attractive for the study of quantum thermoelectric effects.
{"title":"Anomalous Seebeck effect in non-Hermitian double quantum dots","authors":"Pengbin Niu , Li Xu , Hui Yao , Hong-Gang Luo","doi":"10.1016/j.physe.2025.116385","DOIUrl":"10.1016/j.physe.2025.116385","url":null,"abstract":"<div><div>We investigate the thermoelectrical transport in a system of non-Hermitian double quantum dots. For that purpose, we set up a model where two quantum dots are experiencing gain and loss of energy and in proximity to two superconductors. By applying Keldysh Green’s function technique, we study the transmission function, conductance as well as the Seebeck coefficient. We calculate the thermoelectric quantities both analytically and numerically and show that a sign change of the Seebeck coefficient can occur when electrons transport through the Andreev bound states forming on the quantum dots. The sign change is induced by the competition of superconducting pairing potential and PT-symmetric complex potential, when the system passes through the exceptional point. These findings may be attractive for the study of quantum thermoelectric effects.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"175 ","pages":"Article 116385"},"PeriodicalIF":2.9,"publicationDate":"2025-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145267670","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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