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

{"title":"Optical absorption of biased bilayer graphene due to electron–phonon coupling and longitudinal magnetic field","authors":"Hamed Rezania ,&nbsp;Farshad Azizi","doi":"10.1016/j.physe.2025.116276","DOIUrl":"10.1016/j.physe.2025.116276","url":null,"abstract":"<div><div>Electronic and optical properties of both simple and bernal stacked bilayer graphenes taking into account the effects of interaction between electrons and Einstein phonons have been addressed. Also the magnetic field is applied perpendicular to the plane of bilayer graphene. We study the frequency dependence of absorption rate of electromagnetic wave in bilayer graphene due to magnetic field strength and electron–phonon coupling. Green’s function method has been implemented to obtain electronic properties of the system in the context of Holstein model Hamiltonian. One loop electronic self-energy of the model Hamiltonian has been obtained in order to find interacting electronic Green’s function. Optical absorption rate of electromagnetic wave in bilayer graphene due to electron–phonon coupling can be readily found using interacting Green’s function based on Kubo formula. Our results show turning on electron–phonon coupling leads to reduction of band gap in density of states of bernal stacked bilayer graphene. Also a peak appears in frequency dependence of optical absorption rate of bernal stacked bilayer graphene due to electron–phonon coupling and magnetic field. The Drude wight in absorption rate of electromagnetic wave increases with magnetic field with increase of magnetic field strength for stacking types of bilayer graphene.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"172 ","pages":"Article 116276"},"PeriodicalIF":2.9,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143918435","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":"The connection between Hill's nanothermodynamics and Tsallis non-extensive statistical mechanics: Extracting the thermodynamic properties of a nanosystem","authors":"N. Maniotis,&nbsp;N. Frangis","doi":"10.1016/j.physe.2025.116285","DOIUrl":"10.1016/j.physe.2025.116285","url":null,"abstract":"<div><div>Based on the entropy formulation of Tsallis, in the context of non-extensive statistical thermodynamics and the fundamental works of Hill on thermodynamics of small systems (nanothermodynamics), a connection between these two branches of thermodynamics has been made through a new theoretical approach that estimates the equilibrium probability distribution of the size of, deposited on quartz, silicon nanocrystals which are an example of the completely open statistical ensemble. This ensemble describes the behavior of small systems in which the extensive variables, such as the amount of matter in the system, fluctuate under the constraint that intensive variables of temperature, pressure and chemical potential are fixed by the surroundings. The silicon nanocrystals showed a columnar structure for film thicknesses in the range of 5–30 nm. We observed that the size distribution of silicon nanocrystals, is an overlay of q-distributions. Thermodynamic properties of the nanocrystals such as the chemical potential values at different scales and the entropy were obtained after fitting with experimental data collected in different stages of film grow. Those data were taken from literature and correspond to the experimental distributions obtained for three characteristic values of nanocrystalline film thickness, namely 5, 10 and 20 nm. The good agreement between experiment and theory signifies the validity of our model.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"172 ","pages":"Article 116285"},"PeriodicalIF":2.9,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143908313","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":"Size effects on the magnetism and magnetocaloric properties of a polymeric Ising chain","authors":"L.F. de Castro ,&nbsp;C.V. Morais ,&nbsp;F.M. Zimmer ,&nbsp;M. Schmidt","doi":"10.1016/j.physe.2025.116272","DOIUrl":"10.1016/j.physe.2025.116272","url":null,"abstract":"<div><div>We investigate the magnetism and magnetocaloric properties of a mixed-spin Ising chain composed of pentagonal pyramids with spin-1/2 particles on the pentagonal ring and a spin-1 particle on the pyramid top. By considering polymeric chains composed of a different number of pentagonal pyramids, size effects on magnetization and magnetocaloric effect were evaluated within exact enumeration. In the absence of crystal field, our results show that the increase of the chain size reduces the maximum isothermal entropy change, while the cooling capacity and the relative cooling power exhibit a weak dependence on size. On the other hand, for strengths of the crystal field near a ground-state phase transition, maximum isothermal entropy change, cooling capacity, and relative cooling power are markedly enhanced by the increase in the chain size. Therefore, our results indicate that proximity to a ground-state phase transition can lead to significant size effects on the magnetocaloric properties of polymeric mixed-spin chain magnets.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"172 ","pages":"Article 116272"},"PeriodicalIF":2.9,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143918436","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":"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":"Synthesis, characterization, and self-powered UV photodetection properties of GaS","authors":"Qinxi Cui,&nbsp;Lei Wang,&nbsp;Xiaohong Ji","doi":"10.1016/j.physe.2025.116281","DOIUrl":"10.1016/j.physe.2025.116281","url":null,"abstract":"<div><div>The band gap of GaS ranges from 3.05 eV to 2.6 eV as the number of layers increases from monolayer to bulk, making GaS more suitable for blue-ultraviolet photodetection applications. In this study, mono-phase GaS was obtained directly on the Ga metal surface at optimized vulcanization conditions. The single-crystalline characteristic of the fabricated GaS nanosheets was demonstrated by X-ray diffraction, Raman spectroscopy, and transmittance electron microscope analysis. Metal-semiconductor-metal structured photodetectors based on GaS nanosheets exhibited self-powered photodetection performance with a responsivity of 7.1 mA/W and a detectivity of 1 × 10⁹ Jones under 365 nm illumination. The high self-powered performance of the device is attributed to the asymmetric contact electrodes. In addition, the device showed high photodetection performance with a responsivity as high as 40.1 mA/W and a detectivity of 1 × 10¹⁰ Jones at 3 V bias under a 365 nm light illumination. The work provides a viable reference for preparing GaS and advancing photodetectors for other monochalcogenides.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"172 ","pages":"Article 116281"},"PeriodicalIF":2.9,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143898674","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}