Physica E-low-dimensional Systems & Nanostructures最新文献

{"title":"Electron trapping via magnetic and laser fields in gapped graphene quantum dots","authors":"Ahmed Bouhlal ,&nbsp;Mohammed El Azar ,&nbsp;Aotmane En Naciri ,&nbsp;Elmustapha Feddi ,&nbsp;Ahmed Jellal","doi":"10.1016/j.physe.2025.116273","DOIUrl":"10.1016/j.physe.2025.116273","url":null,"abstract":"<div><div>We study electron scattering in graphene quantum dots (GQDs) under the combined influence of a magnetic field, an energy gap, and circularly polarized laser irradiation. Using the Floquet approach and the Dirac equation, we derive the energy spectrum solutions. The scattering coefficients are calculated explicitly by matching the eigenspinors at the GQD interfaces, revealing a dependence on several physical parameters. In addition, we compute the scattering efficiency, the electron density distribution, and the lifetime of the quasi-bound states. Our numerical results show that the presence of an energy gap and circularly polarized laser irradiation enhances the localization of the electron density within the GQDs, leading to an increase in the lifetime of the quasi-bound states. In particular, the intensity and polarization of the light influence the scattering process, allowing the manipulation of the electron confinement state. These results highlight the importance of combining magnetic fields and polarized light to control electronic transport in graphene nanostructures.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"172 ","pages":"Article 116273"},"PeriodicalIF":2.9,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143887412","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}

{"title":"Electronic properties of semimagnetic double quantum wells under effects of magnetic field and temperature","authors":"H. Azmi ,&nbsp;K. El-Bakkari ,&nbsp;A. Fakkahi ,&nbsp;M. Jaouane ,&nbsp;R. Arraoui ,&nbsp;A. Ed-Dahmouny ,&nbsp;A. Mazouz ,&nbsp;M. Jaafar ,&nbsp;A. Sali ,&nbsp;N. Amri ,&nbsp;H. El Ghazi","doi":"10.1016/j.physe.2025.116274","DOIUrl":"10.1016/j.physe.2025.116274","url":null,"abstract":"<div><div>This study examines the electronic characteristics of a diluted magnetic semiconductor double quantum well (DQW) based on the <span><math><mrow><mtext>CdTe</mtext><mo>/</mo><msub><mtext>Cd</mtext><mrow><mn>1</mn><mo>−</mo><mi>x</mi></mrow></msub><msub><mtext>Mn</mtext><mi>x</mi></msub><mtext>Te</mtext></mrow></math></span> system. Through an in-depth analysis, it assesses how various parameters including the well width (<span><math><mrow><msub><mi>L</mi><mi>w</mi></msub></mrow></math></span>), impurity position (<span><math><mrow><msub><mi>z</mi><mi>i</mi></msub></mrow></math></span>), magnetic field intensity (<span><math><mrow><mi>γ</mi></mrow></math></span>), and temperature (<span><math><mrow><mi>T</mi></mrow></math></span>) affect the binding energy (<span><math><mrow><msub><mi>E</mi><mi>b</mi></msub></mrow></math></span>) and diamagnetic susceptibility (<span><math><mrow><msub><mi>χ</mi><mtext>dia</mtext></msub></mrow></math></span>). Additionally, the investigation considers the spin polaronic shift (<span><math><mrow><msub><mi>E</mi><mtext>sp</mtext></msub></mrow></math></span>), taking into account the same influencing factors. The findings demonstrate that an increasing magnetic field leads to a reduction in <span><math><mrow><msub><mi>E</mi><mi>b</mi></msub></mrow></math></span>, particularly when the impurity is positioned at the center of the well in a semimagnetic DQW structure. Furthermore, the results indicate that a rise in temperature also diminishes <span><math><mrow><msub><mi>E</mi><mi>b</mi></msub></mrow></math></span>. Interestingly, temperature and magnetic field exhibit opposing effects on the spin polaronic shift. Moreover, the <span><math><mrow><msub><mi>χ</mi><mtext>dia</mtext></msub></mrow></math></span> is found to be dependent on the impurity location, DQW geometry, applied magnetic field, and temperature.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"172 ","pages":"Article 116274"},"PeriodicalIF":2.9,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143878559","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}

{"title":"Magnetic properties of monolayer VS2 with or without point defects","authors":"Jingsong Lu ,&nbsp;Can Huang ,&nbsp;Bingjie Liu ,&nbsp;Yanfei Pan ,&nbsp;Jiyu Fan ,&nbsp;Chunlan Ma ,&nbsp;Yan Zhu","doi":"10.1016/j.physe.2025.116277","DOIUrl":"10.1016/j.physe.2025.116277","url":null,"abstract":"<div><div>Two-dimensional (2D) transition metal dichalcogenides (TMDs) are becoming increasingly attractive and beneficial to the development of spintronic devices and integrated circuit technologies. The magnetism of monolayer vanadium disulfide remains debated, with no consensus on whether it exhibits ferromagnetism or remains non-magnetic at room temperature. Herein, based on first-principles calculations, we study the stability and electronic structure of monolayer VS₂ in the 1T and 2H phases. Both phases are ferromagnetic ordering in the ideal structure and the magnetic exchange parameters are obtained through the spin-spiral method. Moreover, through the Monte Carlo simulator, we simulate the variation of magnetic parameters along with the increase in temperature. Finally, according to the Stoner criterion, the magnetic moment around the V point defect may collapse due to the decrease in the density of states at the Fermi level. This provides a theoretical explanation for the prevalent absence of observation of net magnetic moments in experiments.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"172 ","pages":"Article 116277"},"PeriodicalIF":2.9,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143891389","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}

{"title":"Exploring quadratic nodal point and square nodal line in two dimensional binary C4X2 compounds (X = N, P, As)","authors":"Guanqi Wang ,&nbsp;Jiahang Li ,&nbsp;Li Zhou ,&nbsp;Peng Wang ,&nbsp;Xiaoming Zhang ,&nbsp;Hongkuan Yuan ,&nbsp;Tie Yang ,&nbsp;Tianran Yang","doi":"10.1016/j.physe.2025.116279","DOIUrl":"10.1016/j.physe.2025.116279","url":null,"abstract":"<div><div>Recently, the investigation of topological states in two dimensional materials has gained prominence, serving as a complementary area to studies of three dimensional systems. This research presents the exceptional topological properties of the monolayer binary compounds C₄X₂ (X = N, P, As) through theoretical calculations. These compounds are characterized by a simple electronic structure consisting of only two bands near the Fermi energy and their band crossing leads to noteworthy topological features, specifically a quadratic nodal point and a Weyl square nodal line. A comprehensive analysis of the mechanisms underlying band formation and dispersion conditions has been conducted. The edge states associated with these compounds emerge from the nodal point and extend towards the nodal line, exhibiting extensive spatial distribution. The lightweight constituent elements of these materials ensure that both the topological features and edge states maintain stability, even when accounting for spin-orbit coupling effects. To enhance practical applicability, this study has also assessed the strain-dependent behaviors of the topological states alongside the anisotropic mechanical properties of the materials. Collectively, the investigation of these ideal topological states, in conjunction with the stability of the material candidates, lays a robust foundation for future experimental research. This work has the potential to facilitate significant advancements in the rapidly evolving field of two-dimensional topological materials.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"172 ","pages":"Article 116279"},"PeriodicalIF":2.9,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143887413","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}

{"title":"Tailoring and enhancing thermal conductivity in germanene nanotubes: A superior alternative to carbon nanotubes using external fields","authors":"Somayeh Behzad","doi":"10.1016/j.physe.2025.116278","DOIUrl":"10.1016/j.physe.2025.116278","url":null,"abstract":"<div><div>This work examines the thermoelectric behavior of Germanene nanotubes (GeNTs) relative to Carbon nanotubes (CNTs), focusing on the influence of external factors, such as chemical potential and applied fields, on their thermal and electronic behavior. Through the application of the tight-binding model and Kubo formula, thermal conductivity, magnetic susceptibility and thermoelectric figure of merit are systematically analyzed. Findings reveal that GeNTs exhibit notable advantages in both thermal conductivity and magnetic susceptibility, particularly under the influence of external fields. Furthermore, the response of GeNTs to electric and magnetic fields is closely related to variations in nanotube radius and chemical potential which enhances their thermoelectric performance over a wider temperature range. These findings highlight the promise of GeNTs as favorable materials for thermoelectric applications in environments that require significant thermal and electrical performance.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"172 ","pages":"Article 116278"},"PeriodicalIF":2.9,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143891390","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}

{"title":"Nonlinear screening and charge redistribution in periodically doped graphene","authors":"K.A. Baryshnikov,&nbsp;A.V. Gert,&nbsp;Yu.B. Vasilyev,&nbsp;A.P. Dmitriev","doi":"10.1016/j.physe.2025.116250","DOIUrl":"10.1016/j.physe.2025.116250","url":null,"abstract":"<div><div>The screening problem for the Coulomb potential of a charge located in a two-dimensional (2D) system has an intriguing solution with a power law distance screening factor due to out-of-plane electrical fields. This is crucially different from a three-dimensional case with exponential screening. The long-range action of electric fields results in the effective inflow of electrons from high-doped regions to low-doped regions of a 2D heterostructure. In graphene and other materials with a linear energy spectrum for electrons, such an inflow in low-doped regions also occurs, but its effectiveness is dependent on the doping level. It can be used to fabricate high-conducting channels. We propose a theory for determining electron potential and concentration in a graphene sheet periodically doped along one dimension, taking into account all effects of long-range 2D screening. This results in a substantially nonlinear integro-differential problem, which is solved numerically via a computationally cheap algorithm. Similar nonlinear problems arise in a wide range of doped 2D heterostructures made of linear spectrum materials.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"172 ","pages":"Article 116250"},"PeriodicalIF":2.9,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143874548","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}

{"title":"Role of edge reconfiguration in generating corner states in Zigzag graphene nanoribbons","authors":"Wenxuan Jiang ,&nbsp;Zheng-Fang Liu ,&nbsp;Qing-Ping Wu ,&nbsp;Xianbo Xiao","doi":"10.1016/j.physe.2025.116260","DOIUrl":"10.1016/j.physe.2025.116260","url":null,"abstract":"<div><div>The study investigates the significance of edge architecture in graphene nanoribbons and its implications on electronic properties and transport behavior. Particularly, it explores the effects of edge reconstruction on Zigzag graphene nanoribbons, focusing on the impact of (5, 7) edge remodeling caused by Stone–Wales defects on topological features and edge states. The energy band structure and state distribution of the reconfigured Zigzag (5, 7) graphene nanoribbon were examined using the tight-binding model. The findings indicate that the edge reconstruction creates energy gaps in the edge-state bands, resulting in the appearance of corner states at the vertices of rectangular graphene nanoflakes with reconstructed edges. Furthermore, analysis of the boundary atomic structure unveiled an SSH4-like configuration at the edges, forming a topological structure that gives rise to zero-energy corner states and two distinct nonzero-energy corner states. The study also notes a transition of non-zero energy corner states towards zero energy influenced by bulk and edge states, while zero-energy corner states shift towards non-zero energy and some merge with the edge states. Nevertheless, the impact of the staggered potential largely restores the corner states determined by the edge structure. This research underscores the significant implications of Stone–Wales-deficient reconfiguration on the topological properties and edge states of Zigzag graphene nanoribbons, providing a theoretical basis for tailoring electron transport characteristics and guiding the development of advanced optoelectronic devices.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"172 ","pages":"Article 116260"},"PeriodicalIF":2.9,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143860486","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}

{"title":"Entanglement negativity in non-Hermitian PT-symmetric models","authors":"L.S. Lima","doi":"10.1016/j.physe.2025.116271","DOIUrl":"10.1016/j.physe.2025.116271","url":null,"abstract":"<div><div>Topological phase transitions are very common in a variety of quantum systems and are a rising topic in actuality. Here we investigate quantum correlation and entanglement in some non-Hermitian <span><math><mi>PT</mi></math></span>-symmetric quantum systems such as Su–Schrieffer–Heeger (SSH) model, which exhibits chiral symmetry and different phases characterized in terms of a topological invariant. The effective Hermitian Hamiltonian has always a higher dimension than the corresponding non-Hermitian model. We verified the effect of periodic hopping modulation on SSH model that exhibits the non-Hermiticity due to presence of an on-site staggered imaginary potential, on measure of quantum entanglement of mixed state given by the entanglement negativity <span><math><msub><mrow><mi>E</mi></mrow><mrow><mi>N</mi></mrow></msub></math></span>. Since its dissipative non-Hermitian extension modifies the features of the topological trivial phase and topological nontrivial phase, the weak potential respecting the parity-time symmetry (<span><math><mrow><mi>P</mi><mi>T</mi></mrow></math></span>) keeps the energy eigenvalues real.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"172 ","pages":"Article 116271"},"PeriodicalIF":2.9,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143854960","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}

{"title":"Structural, vibrational, elastic, and electronic properties of MgO cluster-assembled monolayers","authors":"Yongliang Yong ,&nbsp;Zhiyong Liu ,&nbsp;Wentao Guo ,&nbsp;Qihua Hou ,&nbsp;Zhenlong Lv ,&nbsp;Gang Liu ,&nbsp;Zhansheng Lu ,&nbsp;Xinxin Wang ,&nbsp;Xinli Li","doi":"10.1016/j.physe.2025.116275","DOIUrl":"10.1016/j.physe.2025.116275","url":null,"abstract":"<div><div>Atomic-thin two-dimensional (2D) cluster-assembled metal oxide monolayers have been pursued as a rapidly emerging class of 2D materials with unprecedented properties and potential for versatile applications. Using stable Mg₆O₆ clusters as building blocks, here, we established two new MgO monolayers (namely g-MgO and r-MgO) that completely differ from the known phases, and explored their growth pattern based on cluster assemblies, structural, vibrational, elastic, and electronic properties by exploiting density functional theory (DFT) calculations. Phonon dispersion calculations reveal both monolayers are dynamically stable. The g-MgO and r-MgO monolayers retain structural integrity at 1200 and 1000 K, respectively. Both monolayers have completely different Raman spectra with unique characters, enabling them to be easily identified them in experiments. The calculated in-plane stiffness and Poisson ratio of g-MgO are 75.69 N/m and 0.40, while that of r-MgO are 62.34 (33.87) N/m and 0.97 (0.53), respectively, revealing the isotropic and anisotropic mechanical response for g-MgO and r-MgO monolayers. The g-MgO (r-MgO) monolayer has direct (indirect) semiconducting properties with a wide bandgap of 4.53 (4.64) eV from HSE06 functional and possesses outstandingly high carrier mobilities (all &gt;2.40 × 10³ cm² V⁻¹ s⁻¹), offering promising potential in advanced electronic and photoelectronic applications.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"172 ","pages":"Article 116275"},"PeriodicalIF":2.9,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143844052","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}

{"title":"Coherent and incoherent phonon transport in graphene/h-BN superlattice: A machine learning potential","authors":"Zihan Tan,&nbsp;Shuo Wang,&nbsp;Yuqi Liu,&nbsp;Yang Xiao,&nbsp;Xiaoye Zhou,&nbsp;Shujun Zhou,&nbsp;Xiaoming Xiu,&nbsp;Haikuan Dong","doi":"10.1016/j.physe.2025.116259","DOIUrl":"10.1016/j.physe.2025.116259","url":null,"abstract":"<div><div>Currently, numerous studies demonstrate two mechanisms of coherent and incoherent phonon transport in superlattices. The graphene/hexagonal boron nitride (h-BN) superlattice has attracted significant attention because of its excellent thermal, electrical, and mechanical properties. In this study, we construct an accurate neuroevolution potential (NEP) model and conduct molecular dynamics (MD) simulations using the GPUMD package to investigate phonon transport behavior in the graphene/h-BN superlattice. We find that with increasing periods, phonons transition from coherent to incoherent transport, with their intersection corresponding to the lowest thermal conductivity. Additionally, we discuss phonon transport under varying temperature conditions. We also explore phonon transport in aperiodic superlattices to further illustrate the impact of structural disorder. This study enhances our understanding of phonon transport in superlattices and has the potential to broaden the application of graphene/h-BN superlattices in thermal management and electronic devices.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"172 ","pages":"Article 116259"},"PeriodicalIF":2.9,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143850430","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}