Pub Date : 2025-10-25DOI: 10.1016/j.physe.2025.116394
M. Mumtaz , M. Shahroz , Mubasher , M. Shahid Khan , Mehwish Hassan , Zubair Ahmad , M. Usman , Danish Rashid , Hassan Tariq
Nanohybrids play an important role in a continuum of energy storage devices and among them cobalt ferrite (CoFe2O4) nanoparticles with multi-walled carbon nanotubes (MWCNTs) and reduced graphene oxide (rGO) nanosheets nanohybrid stands out as versatile nanomaterials due to their high performance for supercapacitor's electrodes. In this study, pure CoFe2O4 nanoparticles and their nanohybrids are successfully synthesized by one-pot hydrothermal method with subsequent ultra-sonication. The structural and morphological characterizations are carried out by X-ray diffraction and scanning electron microscopy. The electrochemical performances are investigated by cyclic voltammetry, galvanostatic charging/discharging, and electrochemical impedance spectroscopy in 1 M NaOH aqueous electrolyte. CoFe2O4/MWCNTs/rGO nanohybrids exhibited good electrochemical properties with high specific capacitance (592 F/g). More importantly, the specific capacitance of CoFe2O4/MWCNTs/rGO nanohybrid asymmetric supercapacitor device retained 89.7 % of initial capacitance after 100 cycles at scan-rate of 100 mV/s. The results suggest that the synthesized CoFe2O4/MWCNTs/rGO nanohybrids are promising candidate for supercapacitors electrodes. Moreover, the use of inexpensive carbon materials (rGO, MWCNTs) with transition metal oxides like CoFe2O4 provides a novel cost-effective tri-nanohybrid [CoFe2O4/MWCNTs/rGO] for commercial energy storage devices.
纳米杂化材料在一系列能量存储器件中发挥着重要作用，其中钴铁氧体（CoFe2O4）纳米颗粒具有多壁碳纳米管（MWCNTs）和还原氧化石墨烯（rGO）纳米片，纳米杂化材料因其在超级电容器电极上的高性能而成为多用途纳米材料。在本研究中，采用一锅水热法制备了纯CoFe2O4纳米粒子及其纳米杂化体。用x射线衍射和扫描电镜对其进行了结构和形态表征。采用循环伏安法、恒流充放电法和电化学阻抗法在1 M NaOH水溶液中研究了其电化学性能。CoFe2O4/MWCNTs/rGO纳米杂化物具有良好的电化学性能，具有较高的比电容（592 F/g）。更重要的是，CoFe2O4/MWCNTs/rGO纳米杂化非对称超级电容器器件在扫描速率为100 mV/s的条件下，经过100次循环后，其比电容保持在初始电容的89.7%。结果表明，合成的CoFe2O4/MWCNTs/rGO纳米杂化物是超级电容器电极的理想候选材料。此外，将廉价的碳材料（rGO、MWCNTs）与CoFe2O4等过渡金属氧化物结合使用，为商用储能装置提供了一种新型的具有成本效益的三纳米混合材料[CoFe2O4/MWCNTs/rGO]。
{"title":"Hybridization of cobalt ferrites nanoparticles with multiwall carbon nanotubes and reduced graphene oxide nanosheets: A path to explore new materials for supercapacitors’ electrode","authors":"M. Mumtaz , M. Shahroz , Mubasher , M. Shahid Khan , Mehwish Hassan , Zubair Ahmad , M. Usman , Danish Rashid , Hassan Tariq","doi":"10.1016/j.physe.2025.116394","DOIUrl":"10.1016/j.physe.2025.116394","url":null,"abstract":"<div><div>Nanohybrids play an important role in a continuum of energy storage devices and among them cobalt ferrite (CoFe<sub>2</sub>O<sub>4</sub>) nanoparticles with multi-walled carbon nanotubes (MWCNTs) and reduced graphene oxide (rGO) nanosheets nanohybrid stands out as versatile nanomaterials due to their high performance for supercapacitor's electrodes. In this study, pure CoFe<sub>2</sub>O<sub>4</sub> nanoparticles and their nanohybrids are successfully synthesized by one-pot hydrothermal method with subsequent ultra-sonication. The structural and morphological characterizations are carried out by X-ray diffraction and scanning electron microscopy. The electrochemical performances are investigated by cyclic voltammetry, galvanostatic charging/discharging, and electrochemical impedance spectroscopy in 1 M NaOH aqueous electrolyte. CoFe<sub>2</sub>O<sub>4</sub>/MWCNTs/rGO nanohybrids exhibited good electrochemical properties with high specific capacitance (592 F/g). More importantly, the specific capacitance of CoFe<sub>2</sub>O<sub>4</sub>/MWCNTs/rGO nanohybrid asymmetric supercapacitor device retained 89.7 % of initial capacitance after 100 cycles at scan-rate of 100 mV/s. The results suggest that the synthesized CoFe<sub>2</sub>O<sub>4</sub>/MWCNTs/rGO nanohybrids are promising candidate for supercapacitors electrodes. Moreover, the use of inexpensive carbon materials (rGO, MWCNTs) with transition metal oxides like CoFe<sub>2</sub>O<sub>4</sub> provides a novel cost-effective tri-nanohybrid [CoFe<sub>2</sub>O<sub>4</sub>/MWCNTs/rGO] for commercial energy storage devices.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"175 ","pages":"Article 116394"},"PeriodicalIF":2.9,"publicationDate":"2025-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145416877","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}
Steerability has recently been formalized as a quantum-information task involving arbitrary bipartite states, which can reveal a hierarchy of quantum entanglement, steering, and Bell nonlocality. Additionally, nonlinear atom–cavity interactions and atomic mutual interactions are considered a potential tool for creating two-qubit nonlocality, steerability, and entanglement. Therefore, by using the intrinsic decoherence model, this work investigates the time-dependent generation of atomic nonlocality, as measured by the CHSH-Bell inequality function, EPR steering, and negativity, between coupled two-level atoms interacting resonantly and off-resonantly with a lossless Kerr-like medium cavity filled by a superposition of coherent fields. Moreover, the mutual interaction between the two-level atoms is controlled by considering both Anti-Ferromagnetic Ising atom-atom coupling and dipole–dipole coupling. The time-dependent generation of atomic nonlocality can be optimized by increasing the non-classicality of the initial coherent cavity state, the lossless Kerr-like medium cavity, anti-ferromagnetic Ising atom-atom coupling, atom–cavity detuning dipole–dipole coupling, and the intrinsic atom–cavity decoherence. It has been found that the capability of the interaction between two atoms inside a coherent cavity to realize two-qubit atomic nonlocality can be enhanced by increasing the anti-ferromagnetic Ising atom-atom coupling, atom–cavity detuning, dipole–dipole coupling, as well as the non-classicality of the superposition of two coherent states. Conversely, this ability can be weakened by increasing the lossless Kerr-like medium cavity and the intrinsic atom–cavity decoherence. Moreover, it has been shown that the generated atomic nonlocalities confirm the hierarchy principle between Bell-nonlocality, steerability, and entanglement. Additionally, through the dynamics of steerability and entanglement, the phenomena of sudden birth and sudden death occur, and their occurrence depends on increasing the atom–cavity interaction parameters.
{"title":"Optimizing nonlocality generation in a two-qubit system coupled off-resonantly to a nonlinear coherent cavity under decoherence","authors":"A.-B.A. Mohamed , E.K. Jaradat , F.M. Aldosari , H.A. Hessian","doi":"10.1016/j.physe.2025.116396","DOIUrl":"10.1016/j.physe.2025.116396","url":null,"abstract":"<div><div>Steerability has recently been formalized as a quantum-information task involving arbitrary bipartite states, which can reveal a hierarchy of quantum entanglement, steering, and Bell nonlocality. Additionally, nonlinear atom–cavity interactions and atomic mutual interactions are considered a potential tool for creating two-qubit nonlocality, steerability, and entanglement. Therefore, by using the intrinsic decoherence model, this work investigates the time-dependent generation of atomic nonlocality, as measured by the CHSH-Bell inequality function, EPR steering, and negativity, between coupled two-level atoms interacting resonantly and off-resonantly with a lossless Kerr-like medium cavity filled by a superposition of coherent fields. Moreover, the mutual interaction between the two-level atoms is controlled by considering both Anti-Ferromagnetic Ising atom-atom coupling and dipole–dipole coupling. The time-dependent generation of atomic nonlocality can be optimized by increasing the non-classicality of the initial coherent cavity state, the lossless Kerr-like medium cavity, anti-ferromagnetic Ising atom-atom coupling, atom–cavity detuning dipole–dipole coupling, and the intrinsic atom–cavity decoherence. It has been found that the capability of the interaction between two atoms inside a coherent cavity to realize two-qubit atomic nonlocality can be enhanced by increasing the anti-ferromagnetic Ising atom-atom coupling, atom–cavity detuning, dipole–dipole coupling, as well as the non-classicality of the superposition of two coherent states. Conversely, this ability can be weakened by increasing the lossless Kerr-like medium cavity and the intrinsic atom–cavity decoherence. Moreover, it has been shown that the generated atomic nonlocalities confirm the hierarchy principle between Bell-nonlocality, steerability, and entanglement. Additionally, through the dynamics of steerability and entanglement, the phenomena of sudden birth and sudden death occur, and their occurrence depends on increasing the atom–cavity interaction parameters.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"175 ","pages":"Article 116396"},"PeriodicalIF":2.9,"publicationDate":"2025-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145363365","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 : 2025-10-24DOI: 10.1016/j.physe.2025.116397
Nguyen Thi Han , Pham The Tan , J. Guerrero-Sanchez , D.M. Hoat
In this work, doping/codoping with transition metals (TM = Mn and Fe) and halogens (Ha = Cl and Br) are proposed for the band structure and magnetism engineering in Janus WSSe monolayer. The calculated band structure and magnetic moment confirm the nonmagnetic direct-gap semiconductor nature of WSSe monolayer. The substitution of single Mn, Fe, and Br impurities magnetizes the monolayer with total magnetic moments of 1.00, 2.00, and 0.94 , respectively. Moreover, the doping also induces feature-rich half-metallicity in WSSe monolayer. In contrast, the monolayer is metallized by Cl doping, while no magnetism is generated. Further, dual doping with TM-Ha pairs and doping with small Cl-TM-Br clusters are also investigated. Unlike the cases of single atom doping, magnetic semiconductor nature is obtained in these cases, where strong spin splitting is generated by multiple mid-gap energy states. It is found that the magnetic and electronic properties are determined primarily by Mn/Fe impurities and W atoms around doping sites, where the contribution from halogen impurities is negligible. The role of charge loser of Mn/Fe atoms and charge gainer of Cl/Br atoms is also confirmed through Bader charge analysis. Moreover, the calculated effective Bader charges of constituent atoms also allow analyzing the interactions between pair-impurities or small clusters with the host monolayer. Our findings may suggest effective methods for the functionalization of Janus WSSe monolayer towards spintronic applications.
{"title":"First-principles study of Janus WSSe monolayer doped/co-doped with transition metals and halogens","authors":"Nguyen Thi Han , Pham The Tan , J. Guerrero-Sanchez , D.M. Hoat","doi":"10.1016/j.physe.2025.116397","DOIUrl":"10.1016/j.physe.2025.116397","url":null,"abstract":"<div><div>In this work, doping/codoping with transition metals (TM = Mn and Fe) and halogens (Ha = Cl and Br) are proposed for the band structure and magnetism engineering in Janus WSSe monolayer. The calculated band structure and magnetic moment confirm the nonmagnetic direct-gap semiconductor nature of WSSe monolayer. The substitution of single Mn, Fe, and Br impurities magnetizes the monolayer with total magnetic moments of 1.00, 2.00, and 0.94 <span><math><msub><mrow><mi>μ</mi></mrow><mrow><mi>B</mi></mrow></msub></math></span>, respectively. Moreover, the doping also induces feature-rich half-metallicity in WSSe monolayer. In contrast, the monolayer is metallized by Cl doping, while no magnetism is generated. Further, dual doping with TM-Ha pairs and doping with small Cl-TM-Br clusters are also investigated. Unlike the cases of single atom doping, magnetic semiconductor nature is obtained in these cases, where strong spin splitting is generated by multiple mid-gap energy states. It is found that the magnetic and electronic properties are determined primarily by Mn/Fe impurities and W atoms around doping sites, where the contribution from halogen impurities is negligible. The role of charge loser of Mn/Fe atoms and charge gainer of Cl/Br atoms is also confirmed through Bader charge analysis. Moreover, the calculated effective Bader charges of constituent atoms also allow analyzing the interactions between pair-impurities or small clusters with the host monolayer. Our findings may suggest effective methods for the functionalization of Janus WSSe monolayer towards spintronic applications.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"175 ","pages":"Article 116397"},"PeriodicalIF":2.9,"publicationDate":"2025-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145363432","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 : 2025-10-24DOI: 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":"2025-10-24","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 : 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}
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