Pub Date : 2026-01-01Epub 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":"2026-01-01","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 : 2026-01-01Epub Date: 2025-11-13DOI: 10.1016/j.physe.2025.116417
Xiang Huang , Weiye Hou , Jie Zhang , Jiaye Gu , Qin Jin , Hongbo Wu , Zhe Zhang
Goldene, the first experimentally realized free-standing two-dimensional monolayer of elemental gold, exhibits unique dimension-driven effects and outstanding physicochemical properties. However, its environmental stability remains a challenge, and the synergistic effects of defects and mechanical strain on its surface electronics and oxidation behavior have yet to be fully understood. In this work, by jointly considering surface defects and strain effects, we systematically investigated the adsorption and dissociation behavior of oxygen molecules on goldene surfaces using first-principles calculations with advanced machine learning molecular dynamics (MLMD) simulations. On defective goldene, O2 adsorption is strengthened and the dissociation barrier is reduced from 1.81 eV to 0.57 eV. Under tensile strain, adsorption increases nearly linearly, with a further decrease in the barrier that weakens oxidation resistance. Electronic structure analysis reveals that the tensile strain shifts the Au d-band center upward, thereby enhancing the hybridization between O 2p and Au 5d orbitals, which fundamentally promotes O2 activation. In particular, at larger tensile strains (∼5 %), the barrier disappearance enables spontaneous O2 activation on defective goldene surface through synergistic strain-vacancy effects. Our detailed MLMD simulations further validate these findings, demonstrating the O2 dissociation pathway evolution and reaction dynamics in the strained defective system. This work elucidates how vacancy defects and strain synergistically regulate goldene's surface chemistry, advancing microscopic understanding of the physical picture of surface reactivity control in 2D metallic materials and offer valuable guidance for designing stable and highly active 2D metal-based catalysts.
{"title":"Defect-strain synergy tunes Au d-band center and triggers spontaneous O2 activation on goldene","authors":"Xiang Huang , Weiye Hou , Jie Zhang , Jiaye Gu , Qin Jin , Hongbo Wu , Zhe Zhang","doi":"10.1016/j.physe.2025.116417","DOIUrl":"10.1016/j.physe.2025.116417","url":null,"abstract":"<div><div>Goldene, the first experimentally realized free-standing two-dimensional monolayer of elemental gold, exhibits unique dimension-driven effects and outstanding physicochemical properties. However, its environmental stability remains a challenge, and the synergistic effects of defects and mechanical strain on its surface electronics and oxidation behavior have yet to be fully understood. In this work, by jointly considering surface defects and strain effects, we systematically investigated the adsorption and dissociation behavior of oxygen molecules on goldene surfaces using first-principles calculations with advanced machine learning molecular dynamics (MLMD) simulations. On defective goldene, O<sub>2</sub> adsorption is strengthened and the dissociation barrier is reduced from 1.81 eV to 0.57 eV. Under tensile strain, adsorption increases nearly linearly, with a further decrease in the barrier that weakens oxidation resistance. Electronic structure analysis reveals that the tensile strain shifts the Au d-band center upward, thereby enhancing the hybridization between O 2p and Au 5d orbitals, which fundamentally promotes O<sub>2</sub> activation. In particular, at larger tensile strains (∼5 %), the barrier disappearance enables spontaneous O<sub>2</sub> activation on defective goldene surface through synergistic strain-vacancy effects. Our detailed MLMD simulations further validate these findings, demonstrating the O<sub>2</sub> dissociation pathway evolution and reaction dynamics in the strained defective system. This work elucidates how vacancy defects and strain synergistically regulate goldene's surface chemistry, advancing microscopic understanding of the physical picture of surface reactivity control in 2D metallic materials and offer valuable guidance for designing stable and highly active 2D metal-based catalysts.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"176 ","pages":"Article 116417"},"PeriodicalIF":2.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145569532","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 : 2026-01-01Epub 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":"2026-01-01","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 : 2026-01-01Epub 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":"2026-01-01","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 : 2026-01-01Epub Date: 2025-10-08DOI: 10.1016/j.physe.2025.116386
F. Castañeda-Ramírez , M. Martínez-Mares , A.M. Martínez-Argüello
The statistical fluctuations of the voltage across a quantum wire in a four-terminal arrangement, where two of the terminals are used as probes while the other two are used to establish a flux current, is studied in the single channel case. The quantum wire to be measured consists of a chaotic microcavity or a disordered conductor in the presence of one of the three symmetry classes: orthogonal, unitary, or symplectic. Using the circular ensembles of random matrix theory or the Dorokov–Mello–Pereyra–Kumar (DMPK) equation, the statistical distribution of the voltage is reduced to quadratures for noninvasive probes which is solved numerically. Numerical simulations from random matrix theory or for the DMPK equation are performed for any coupling strength of the probes. For the chaotic cavity the effect of the symmetry class is clearly manifested through the weak and weak anti-localization phenomena for the orthogonal and symplectic symmetry classes, respectively. A similar effect is found, but with respect to the degree of disorder in a quantum wire as it evolves from strong to weak disorder: a simple correspondence between the label of the symmetry class and the degree of disorder, is found.
{"title":"Voltage fluctuations in a four-terminal quantum device with orthogonal, unitary or symplectic symmetry","authors":"F. Castañeda-Ramírez , M. Martínez-Mares , A.M. Martínez-Argüello","doi":"10.1016/j.physe.2025.116386","DOIUrl":"10.1016/j.physe.2025.116386","url":null,"abstract":"<div><div>The statistical fluctuations of the voltage across a quantum wire in a four-terminal arrangement, where two of the terminals are used as probes while the other two are used to establish a flux current, is studied in the single channel case. The quantum wire to be measured consists of a chaotic microcavity or a disordered conductor in the presence of one of the three symmetry classes: orthogonal, unitary, or symplectic. Using the circular ensembles of random matrix theory or the Dorokov–Mello–Pereyra–Kumar (DMPK) equation, the statistical distribution of the voltage is reduced to quadratures for noninvasive probes which is solved numerically. Numerical simulations from random matrix theory or for the DMPK equation are performed for any coupling strength of the probes. For the chaotic cavity the effect of the symmetry class is clearly manifested through the weak and weak anti-localization phenomena for the orthogonal and symplectic symmetry classes, respectively. A similar effect is found, but with respect to the degree of disorder in a quantum wire as it evolves from strong to weak disorder: a simple correspondence between the label of the symmetry class and the degree of disorder, is found.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"175 ","pages":"Article 116386"},"PeriodicalIF":2.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145267671","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 : 2026-01-01Epub Date: 2025-10-24DOI: 10.1016/j.physe.2025.116399
Irina V. Lebedeva , Andrey M. Popov , Yulia G. Polynskaya , Andrey A. Knizhnik , Sergey A. Vyrko , Nikolai A. Poklonski
Twisted graphene layers exhibit extremely low friction for relative sliding. Nevertheless, previous studies suggest that the area contribution to friction for commensurate moiré systems is finite and might restrict macroscopic superlubricity for large layer overlaps. In this paper, we investigate the potential energy surface (PES) for relative displacement of the layers forming moiré patterns (2,1) and (3,1) by accurate density functional theory calculations using the vdW-DF3 functional. The amplitudes of PES corrugations on the order of 0.4 and 0.03 per atom of one layer, respectively, are obtained. The account of structural relaxation doubles this value for the (2,1) pattern, while causing only minimal changes for the (3,1) pattern. We show that different from aligned graphene layers, for moiré patterns, PES minima and maxima can switch their positions upon changing the interlayer distance. The PES shape is closely described by the first spatial Fourier harmonics both with and without account of structural relaxation. A barrier for relative rotation of the layers to an incommensurate state that can make superlubricity robust is estimated based on the approximated PES. We also derive a set of measurable physical properties related to interlayer interaction including shear mode frequency, shear modulus and static friction force. Furthermore, we predict that it should be possible to observe domain walls separating commensurate domains, each comprising a large number of moiré pattern unit cells, and provide estimates of their characteristics.
{"title":"Robust structural superlubricity of twisted graphene bilayer and domain walls between commensurate moiré pattern domains from first-principles calculations","authors":"Irina V. Lebedeva , Andrey M. Popov , Yulia G. Polynskaya , Andrey A. Knizhnik , Sergey A. Vyrko , Nikolai A. Poklonski","doi":"10.1016/j.physe.2025.116399","DOIUrl":"10.1016/j.physe.2025.116399","url":null,"abstract":"<div><div>Twisted graphene layers exhibit extremely low friction for relative sliding. Nevertheless, previous studies suggest that the area contribution to friction for commensurate moiré systems is finite and might restrict macroscopic superlubricity for large layer overlaps. In this paper, we investigate the potential energy surface (PES) for relative displacement of the layers forming moiré patterns (2,1) and (3,1) by accurate density functional theory calculations using the vdW-DF3 functional. The amplitudes of PES corrugations on the order of 0.4 and 0.03 <span><math><mrow><mi>μ</mi><mi>eV</mi></mrow></math></span> per atom of one layer, respectively, are obtained. The account of structural relaxation doubles this value for the (2,1) pattern, while causing only minimal changes for the (3,1) pattern. We show that different from aligned graphene layers, for moiré patterns, PES minima and maxima can switch their positions upon changing the interlayer distance. The PES shape is closely described by the first spatial Fourier harmonics both with and without account of structural relaxation. A barrier for relative rotation of the layers to an incommensurate state that can make superlubricity robust is estimated based on the approximated PES. We also derive a set of measurable physical properties related to interlayer interaction including shear mode frequency, shear modulus and static friction force. Furthermore, we predict that it should be possible to observe domain walls separating commensurate domains, each comprising a large number of moiré pattern unit cells, and provide estimates of their characteristics.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"175 ","pages":"Article 116399"},"PeriodicalIF":2.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145416878","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 : 2026-01-01Epub Date: 2025-09-06DOI: 10.1016/j.physe.2025.116358
Arneet Kaur , Pradip Nandi , Abir De Sarkar
In the quest for efficient energy conversion materials, we investigate piezoelectric properties of tin nitride halide (SnNX) through strategic design of vertical and lateral SnNCl/SnNBr heterostructures, using first-principles calculations. Two vertical configurations (HB-I and HB-II), based on the choice of the basal atomic layer (SnNBr or SnNCl), are studied with six stacking sequences featuring parallel and antiparallel orientations. The interlayer registry index highlights the dominant role of interface interactions in determining the energy landscape. HB-II configuration exhibits a type-II band alignment for all stacking orders (AA, AB, AC). While only the AC stacking order of HB-I displays a type-II band alignment, which correlates with the reversal in the direction of charge polarization. Lateral heterostructures composed of eight-unit cells of SnNCl and SnNBr [(SnNCl)8/(SnNBr)8] are also constructed along armchair and zigzag directions, revealing mixed band alignment at the interfaces. A comprehensive analysis indicates that interfacial charge polarization critically determines the piezoelectric response. The out-of-plane piezoelectric strain coefficient, reaches 90 p.m./V in the vertical heterostructure, comparable to leading bulk perovskites. Our findings provide a deeper understanding of band alignment and piezoelectricity in SnNCl/SnNBr heterostructures, paving the way for future experimental efforts to design advanced 2D energy conversion materials with tailored properties.
{"title":"Charge polarization-driven type-II band alignment and enhanced piezoelectricity in tin nitride halide heterostructures","authors":"Arneet Kaur , Pradip Nandi , Abir De Sarkar","doi":"10.1016/j.physe.2025.116358","DOIUrl":"10.1016/j.physe.2025.116358","url":null,"abstract":"<div><div>In the quest for efficient energy conversion materials, we investigate piezoelectric properties of tin nitride halide (SnNX) through strategic design of vertical and lateral SnNCl/SnNBr heterostructures, using first-principles calculations. Two vertical configurations (HB-I and HB-II), based on the choice of the basal atomic layer (SnNBr or SnNCl), are studied with six stacking sequences featuring parallel and antiparallel orientations. The interlayer registry index highlights the dominant role of interface interactions in determining the energy landscape. HB-II configuration exhibits a type-II band alignment for all stacking orders (AA, AB, AC). While only the AC stacking order of HB-I displays a type-II band alignment, which correlates with the reversal in the direction of charge polarization. Lateral heterostructures composed of eight-unit cells of SnNCl and SnNBr [(SnNCl)<sub>8</sub>/(SnNBr)<sub>8</sub>] are also constructed along armchair and zigzag directions, revealing mixed band alignment at the interfaces. A comprehensive analysis indicates that interfacial charge polarization critically determines the piezoelectric response. The out-of-plane piezoelectric strain coefficient, <span><math><mrow><msub><mi>d</mi><mn>33</mn></msub></mrow></math></span> reaches 90 p.m./V in the vertical heterostructure, comparable to leading bulk perovskites. Our findings provide a deeper understanding of band alignment and piezoelectricity in SnNCl/SnNBr heterostructures, paving the way for future experimental efforts to design advanced 2D energy conversion materials with tailored properties.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"175 ","pages":"Article 116358"},"PeriodicalIF":2.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145061261","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 : 2025-10-01Epub Date: 2025-08-09DOI: 10.1016/j.physe.2025.116351
M.P. Telenkov, Yu.A. Mityagin, D.S. Korchagin
Electron scattering with longitudinal polar optical phonons in a quantizing magnetic field tilted to the plane of quantum well layers is studied. The expressions are derived for the electron scattering rate due to longitudinal polar optical phonon emission in a tilted quantizing magnetic field. The effect of variations in both the magnitude and orientation of the magnetic field on the electron-phonon scattering processes is studied. The different relation between the inter-subband spacing and the optical phonon energy are considered – when the inter-subband spacing is greater than, equal to, and lower than the optical phonon energy. Principal transformation of the inter-subband scattering rate dependence on the quantizing component of the magnetic field – from oscillatory to monotonic – was found to occur when inter-subband spacing comes closer to optical phonon frequency.
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Pub Date : 2025-10-01Epub Date: 2025-07-30DOI: 10.1016/j.physe.2025.116333
Shiming Zheng, E.S. Khramtsov, I.V. Ignatiev
A microscopic model of a heterostructure with a quantum well (QW) is proposed to study exciton properties in an external electric field. The effect of an electric field ranging from 0 to 6 kV/cm applied to a GaAs/AlGaAs QW structure in the growth direction is studied for several QWs of various widths up to 100 nm. The three-dimensional Schrödinger equation (SE) for the exciton is numerically solved using the finite difference method. Wave functions and energies of several states of the heavy-hole and light-hole excitons are calculated. The dependencies of exciton state energy, binding energy, radiative broadening, and static dipole moment on the applied electric field are determined. Additionally, the threshold for exciton dissociation in the 100-nm QW is established. Furthermore, we calculate an electric-field-induced shift in the center of mass of heavy-hole and light-hole excitons in the QWs. Finally, we simulate the reflection spectra of heterostructures with GaAs/AlGaAs QWs under an electric field using the calculated energies, radiative broadenings, and phases of exciton resonances.
{"title":"Effect of electric field on excitons in wide quantum wells","authors":"Shiming Zheng, E.S. Khramtsov, I.V. Ignatiev","doi":"10.1016/j.physe.2025.116333","DOIUrl":"10.1016/j.physe.2025.116333","url":null,"abstract":"<div><div>A microscopic model of a heterostructure with a quantum well (QW) is proposed to study exciton properties in an external electric field. The effect of an electric field ranging from 0 to 6 kV/cm applied to a GaAs/AlGaAs QW structure in the growth direction is studied for several QWs of various widths up to 100 nm. The three-dimensional Schrödinger equation (SE) for the exciton is numerically solved using the finite difference method. Wave functions and energies of several states of the heavy-hole and light-hole excitons are calculated. The dependencies of exciton state energy, binding energy, radiative broadening, and static dipole moment on the applied electric field are determined. Additionally, the threshold for exciton dissociation in the 100-nm QW is established. Furthermore, we calculate an electric-field-induced shift in the center of mass of heavy-hole and light-hole excitons in the QWs. Finally, we simulate the reflection spectra of heterostructures with GaAs/AlGaAs QWs under an electric field using the calculated energies, radiative broadenings, and phases of exciton resonances.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"174 ","pages":"Article 116333"},"PeriodicalIF":2.9,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144781827","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 : 2025-10-01Epub Date: 2025-08-09DOI: 10.1016/j.physe.2025.116350
Hayet Saghrouni , Lotfi Beji
In this study, dysprosium oxide thin films with a thickness of 15 nm were deposited onto an n-type gallium arsenide (111) substrate using electron beam evaporation under ultra-high vacuum conditions. The deposition process, carried out at 250 °C and followed by thermal annealing at 400 °C, yielded uniformly smooth films with good structural quality and interfacial integrity. Structural analysis through scanning electron microscopy and X-ray diffraction revealed uniform triangular surface features and confirmed the cubic phase of dysprosium oxide, with crystallographic alignment to the gallium arsenide substrate. Fourier-transform infrared spectroscopy validated the formation of dysprosium–oxygen bonds. The optical properties were extracted using spectroscopic ellipsometry. The refractive index exhibited normal dispersion, and the optical band gap was determined to be 4.09 ± 0.03 eV. Wemple–DiDomenico modeling provided the oscillator energy (5.02 ± 0.05 eV) and dispersion energy (9.80 ± 0.07 eV), while dielectric function analysis identified sharp electronic transitions attributed to intra-4f states of trivalent dysprosium ions. In the infrared region, classical dispersion relations enabled the extraction of key parameters, including the high-frequency dielectric constant (3.28 ± 0.05), plasma frequency (1.81 ± 0.04) × 1014 Hz, carrier relaxation time (2.26 ± 0.03) × 10−15 s, and carrier concentration to effective mass ratio ((3.69 ± 0.08) × 1047 g−1 cm−3). Energy loss analysis through surface and volume energy loss functions revealed distinct plasmonic and interband excitation features. Optical conductivity measurements highlighted excitonic and bulk plasmon activity in the 2.7–3.8 eV range. Nonlinear optical behavior was evaluated using Miller's rule, yielding a linear susceptibility of 0.155 ± 0.004 esu, a third-order susceptibility of (9.74 ± 0.21) × 10−14 esu, and a nonlinear refractive index of (2.40 ± 0.06) × 10−12 esu. Overall, the dysprosium oxide thin films demonstrated excellent crystallinity, high optical quality, and strong third-order nonlinear response, positioning them as promising candidates for advanced optoelectronic and photonic applications, including ultraviolet photodetectors, nonlinear optical modulators, and integrated optical devices.
{"title":"Structural and optical characterization of electron Beam–Deposited Dy2O3 thin films on n-GaAs(111) substrate for photonic applications","authors":"Hayet Saghrouni , Lotfi Beji","doi":"10.1016/j.physe.2025.116350","DOIUrl":"10.1016/j.physe.2025.116350","url":null,"abstract":"<div><div>In this study, dysprosium oxide thin films with a thickness of 15 nm were deposited onto an n-type gallium arsenide (111) substrate using electron beam evaporation under ultra-high vacuum conditions. The deposition process, carried out at 250 °C and followed by thermal annealing at 400 °C, yielded uniformly smooth films with good structural quality and interfacial integrity. Structural analysis through scanning electron microscopy and X-ray diffraction revealed uniform triangular surface features and confirmed the cubic phase of dysprosium oxide, with crystallographic alignment to the gallium arsenide substrate. Fourier-transform infrared spectroscopy validated the formation of dysprosium–oxygen bonds. The optical properties were extracted using spectroscopic ellipsometry. The refractive index exhibited normal dispersion, and the optical band gap was determined to be 4.09 ± 0.03 eV. Wemple–DiDomenico modeling provided the oscillator energy (5.02 ± 0.05 eV) and dispersion energy (9.80 ± 0.07 eV), while dielectric function analysis identified sharp electronic transitions attributed to intra-4f states of trivalent dysprosium ions. In the infrared region, classical dispersion relations enabled the extraction of key parameters, including the high-frequency dielectric constant (3.28 ± 0.05), plasma frequency (1.81 ± 0.04) × 10<sup>14</sup> Hz, carrier relaxation time (2.26 ± 0.03) × 10<sup>−15</sup> s, and carrier concentration to effective mass ratio ((3.69 ± 0.08) × 10<sup>47</sup> g<sup>−1</sup> cm<sup>−3</sup>). Energy loss analysis through surface and volume energy loss functions revealed distinct plasmonic and interband excitation features. Optical conductivity measurements highlighted excitonic and bulk plasmon activity in the 2.7–3.8 eV range. Nonlinear optical behavior was evaluated using Miller's rule, yielding a linear susceptibility of 0.155 ± 0.004 esu, a third-order susceptibility of (9.74 ± 0.21) × 10<sup>−14</sup> esu, and a nonlinear refractive index of (2.40 ± 0.06) × 10<sup>−12</sup> esu. Overall, the dysprosium oxide thin films demonstrated excellent crystallinity, high optical quality, and strong third-order nonlinear response, positioning them as promising candidates for advanced optoelectronic and photonic applications, including ultraviolet photodetectors, nonlinear optical modulators, and integrated optical devices.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"174 ","pages":"Article 116350"},"PeriodicalIF":2.9,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144810454","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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