Physics Letters APub Date : 2025-03-12DOI: 10.1016/j.physleta.2025.130420
Sharad Kumar Upadhyay
{"title":"Coulomb drag study of dynamic screening in graphene inhomogeneous bilayer system","authors":"Sharad Kumar Upadhyay","doi":"10.1016/j.physleta.2025.130420","DOIUrl":"10.1016/j.physleta.2025.130420","url":null,"abstract":"<div><div>We study coulomb drag phenomena in doped-graphene based electron-electron (e-e) bilayer systems described by non-interacting massless Dirac fermions separated by an insulating layer. The non-zero frequency dependent dynamic screening is taken into account to include the correlations between the two layer using the random phase approximation (RPA) method for long-range and weak interaction limits. Analytically, the frequency-dependent/dynamic response function is presented at finite and non-finite temperatures to consider the dynamic screening. At low temperatures, drag resistivity shows an usual Fermi-liquid behavior. However, a marked improvement has been found in the predictions of the conventional static interaction. Zero-temperature dependent dynamic screening results show <span><math><mo>≥</mo><mn>20</mn><mtext>%</mtext></math></span> enhanced drag resistivity (<span><math><msub><mrow><mi>ρ</mi></mrow><mrow><mi>D</mi></mrow></msub></math></span>) compared to static. Similarly, the dynamic screening at finite temperature result in a significant enhancement and qualitative change than non-finite temperature. The structure concern to non-homogeneous dielectric medium (NHDM) is also studied to consider the screening effects of substrate and uppermost layer into account. The introduction of NHDM structure finds a marked improvement compared to homogeneous dielectric medium (HDM).</div></div>","PeriodicalId":20172,"journal":{"name":"Physics Letters A","volume":"542 ","pages":"Article 130420"},"PeriodicalIF":2.3,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143611565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Physics Letters APub Date : 2025-03-12DOI: 10.1016/j.physleta.2025.130431
Tong-Hui Zhou , Lin Long , Zhi-Qiang Fan
{"title":"Mechanical force adjusts the bonding orientation with respect to the electrode to regulate electronic transport in single-molecule devices","authors":"Tong-Hui Zhou , Lin Long , Zhi-Qiang Fan","doi":"10.1016/j.physleta.2025.130431","DOIUrl":"10.1016/j.physleta.2025.130431","url":null,"abstract":"<div><div>The paper studies the mechanical force adjusting the bonding orientation with respect to the molecule to regulate electronic transport in single-molecule devices by using first-principle calculations. We designed molecular junctions by connecting tetraphenylene molecules to gold electrodes via amino or pyridine anchoring groups. By applying horizontal compressive force, the bonding orientation angle was adjusted from 0° to 45°, and the corresponding current-voltage characteristics were calculated. For the single-molecule device connected to gold electrodes via amino group, the transmission spectra exhibited a pronounced leftward shift as the orientation angle increased, accompanied by a gradual rise in the current. In contrast, the single-molecule device connected to gold electrodes via pyridine group showed no significant shift in the transmission spectra under mechanical compression. When the orientation angle increases to 30° and 45°, significant negative differential resistance behaviors are observed in the molecular devices. Our research results provide an understanding of the influence of bonding orientation on the electronic transport properties in molecular devices, and offering an approach to the realization of molecular functional devices.</div></div>","PeriodicalId":20172,"journal":{"name":"Physics Letters A","volume":"542 ","pages":"Article 130431"},"PeriodicalIF":2.3,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143642225","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":"High-performance achromatic metalens in the long-wavelength infrared regime","authors":"Tianqi Gu , Yihao Zhang , Hangbin Cai , Dawei Tang","doi":"10.1016/j.physleta.2025.130430","DOIUrl":"10.1016/j.physleta.2025.130430","url":null,"abstract":"<div><div>In recent decades, metasurfaces have shown remarkable advancements in the development of integrated and miniaturized optical devices. Among these, metalenses have emerged as a prominent and significant area of research. In this paper, a broadband achromatic metalens is designed to operate across a wide wavelength range, specifically from 9.6 μm to 11.6 μm. To efficiently achieve the optimization of initial metalens parameters, we employ an envelope-based layering strategy that divides the sample space into multiple adjacent floors. This approach effectively reduces the loss rate and computational burden in a comprehensive manner. An enhanced Archimedes optimization algorithm is utilized to obtain the optimal solution. It incorporates the opposition-based learning with Sine map and elite retention strategy to enhance the search capability and avoid getting trapped in local optima. Following the optimization process, the proposed metalens achieves an average focusing efficiency of 53.64 %, with chromatic aberration correction accomplished at a coefficient of variation of only 2.27 %. This accomplishment signifies a substantial advancement in the field of achromatic metalenses.</div></div>","PeriodicalId":20172,"journal":{"name":"Physics Letters A","volume":"542 ","pages":"Article 130430"},"PeriodicalIF":2.3,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143642224","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}
Physics Letters APub Date : 2025-03-10DOI: 10.1016/j.physleta.2025.130428
Wanglong Zhao, Shixing Yu, Na Kou
{"title":"Stable divergence angle control of OAM vortex beams with different modes","authors":"Wanglong Zhao, Shixing Yu, Na Kou","doi":"10.1016/j.physleta.2025.130428","DOIUrl":"10.1016/j.physleta.2025.130428","url":null,"abstract":"<div><div>In this letter, we propose a stable divergence angle control method for orbital angular momentum (OAM) beams with different modes. Typically, OAM beams with different mode numbers exhibit distinct divergence angles even under the same antenna aperture. This greatly limits its long-distance communication capability since receiving the OAM beams of different modes with varying divergence angle is difficult when the receiving antenna is usually fixed. Based on the directivity function of OAM beam generated by the uniform concentric circular array (UCCA), local extremum value can be found at the divergence angle. Hence, we can calculate the derivative of directivity functions to obtain the required excitation amplitude distribution. By changing the excitation amplitude of each ring in the UCCA without adjustment of the antenna aperture, the OAM beams with modes <em>l</em> = 1, 2 and 3 can reach the same divergence angle. Both simulated and measured results verify the correctness of the proposed method and it can provide references for applying OAM waves to the practical long-distance wireless communication systems.</div></div>","PeriodicalId":20172,"journal":{"name":"Physics Letters A","volume":"541 ","pages":"Article 130428"},"PeriodicalIF":2.3,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143609398","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":"Interaction imbalanced spin-orbit coupled quantum droplets","authors":"Sonali Gangwar , Rajamanickam Ravisankar , S.I. Mistakidis , Paulsamy Muruganandam , Pankaj Kumar Mishra","doi":"10.1016/j.physleta.2025.130426","DOIUrl":"10.1016/j.physleta.2025.130426","url":null,"abstract":"<div><div>We explore the ground states and quench dynamics of spin-orbit coupled (SOC) one-dimensional two-component quantum droplets featuring intracomponent interaction imbalance. A plethora of miscible ground state stripe and standard flat-top or Gaussian droplets is found depending on the interplay between the SOC wavenumber and interactions. Deformations among these states are accompanied by controllable spin population transfer. Upon considering a trap we identify a transition from a bound to a trapped gas many-body state, captured through a sign change of the chemical potential, which occurs at lower (larger) atom numbers for tighter traps (stronger interactions). The droplets breathing frequency is found to increase for larger intracomponent interaction ratio or reaches a maximum at SOC wavenumbers where the transition from non-modulated flat-top to stripe droplets exists. Dynamical droplet fragmentation occurs for abrupt changes of the Rabi-coupling, while large amplitude quenches of the SOC wavenumber trigger spin-demixed counterpropagating untrapped droplets or in-trap out-of-phase oscillating ones. Our results offer insights into controlled spin-mixing processes in droplets and the potential excitation of magnetic bound states, opening avenues for further research in this field.</div></div>","PeriodicalId":20172,"journal":{"name":"Physics Letters A","volume":"542 ","pages":"Article 130426"},"PeriodicalIF":2.3,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143645054","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}
Physics Letters APub Date : 2025-03-10DOI: 10.1016/j.physleta.2025.130425
Konstantin Y. Bliokh
{"title":"On the Ehrenfest theorem and centroids of relativistic particles","authors":"Konstantin Y. Bliokh","doi":"10.1016/j.physleta.2025.130425","DOIUrl":"10.1016/j.physleta.2025.130425","url":null,"abstract":"<div><div>We consider relativistic versions of the Ehrenfest relation between the expectation values of the coordinate and momentum of a quantum particle in free space: <span><math><mi>d</mi><mo>〈</mo><mi>r</mi><mo>〉</mo><mo>/</mo><mi>d</mi><mi>t</mi><mo>=</mo><mo>〈</mo><mi>p</mi><mo>〉</mo><mo>/</mo><mi>m</mi></math></span>. We find that the simple proportionality between the mean velocity and momentum holds true only for the simplest quadratic dispersion (i.e., dependence of the energy on the momentum). For relativistic dispersion, the mean velocity is generally not collinear with the mean momentum, but velocity of the <em>energy centroid</em> is directed along the mean momentum. This is related to the conservation of the Lorentz-boost momentum and has implications in possible decomposition of the mean orbital angular momentum into intrinsic and extrinsic parts. Neglecting the spin/polarization effects, these properties depend solely on the dispersion relation, and can be applied to any waves, including classical electromagnetic or acoustic fields.</div></div>","PeriodicalId":20172,"journal":{"name":"Physics Letters A","volume":"542 ","pages":"Article 130425"},"PeriodicalIF":2.3,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143645052","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}
Physics Letters APub Date : 2025-03-10DOI: 10.1016/j.physleta.2025.130424
Lai-Lai Mi, Jie Wang, Jiang-Peng Yao, Ai-Xia Zhang, Ju-Kui Xue
{"title":"Magnetic induced reflection, resistance and symmetry breaking of atomic matter wave in a two-leg ladder","authors":"Lai-Lai Mi, Jie Wang, Jiang-Peng Yao, Ai-Xia Zhang, Ju-Kui Xue","doi":"10.1016/j.physleta.2025.130424","DOIUrl":"10.1016/j.physleta.2025.130424","url":null,"abstract":"<div><div>The transport of ultracold atoms in a two-leg ladder under non-uniform artificial magnetic field is studied analytically and numerically. Introducing a non-uniform magnetic field as a magnetic barrier produces rich phenomena, similar to the transmission and the reflection of light beams propagating in a non-uniform media. The phase diagram describing atomic transmission and reflection at the magnetic barrier is given. Atomic transport can be effectively controlled by the magnetic field. Interestingly, when atoms transmit through the barrier, magnetic induced resistance and dynamical biased ladder state are observed, offering an efficient dynamical way for realizing the biased ladder phase. Our work provides an theoretical evidence for the coherent control of atomic matter waves in magnetized lattice systems and the design of novel atomic optical devices.</div></div>","PeriodicalId":20172,"journal":{"name":"Physics Letters A","volume":"541 ","pages":"Article 130424"},"PeriodicalIF":2.3,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143609382","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}
Physics Letters APub Date : 2025-03-10DOI: 10.1016/j.physleta.2025.130429
Akbar Abbas , Saad Tariq , Hussain J. Alathlawi , Fadiyah Antar Makin , Areej Al bahir , M. Musa Saad H․-E․
{"title":"High-pressure computational analysis of CsCdF₃: Structural stability, electronic transitions, and thermodynamic properties","authors":"Akbar Abbas , Saad Tariq , Hussain J. Alathlawi , Fadiyah Antar Makin , Areej Al bahir , M. Musa Saad H․-E․","doi":"10.1016/j.physleta.2025.130429","DOIUrl":"10.1016/j.physleta.2025.130429","url":null,"abstract":"<div><div>This study investigates the structural, mechanical, thermal, and electronic properties of CsCdF₃ using the FP-LAPW method within the WIEN2k code. Employing Density Functional Theory (DFT), we analyze CsCdF₃ under pressures up to 40 GPa. Structural stability is confirmed through geometry optimization, phonon stability and the Goldschmidt tolerance factor, while electronic properties are analyzed using the Tran-Blaha modified Becke-Johnson (TB-mBJ) potential. The electronic properties reveal a semiconductor behavior at low pressure, transitioning to an insulating state with an indirect band gap under high pressure. Mechanical stability is verified, with elastic properties such as Bulk Modulus, Young's Modulus, and Poisson's Ratio evaluated. The material exhibits superplasticity, machinability, and anisotropic hardness. Thermal analysis shows the Debye temperature rising to ≈606 K at 40 GPa, while the melting temperature reaches ≈3305 K. CsCdF₃’s wide bandgap, high melting point, and non-magnetic nature make it suitable for shielding magnetic devices under high-pressure conditions.</div></div>","PeriodicalId":20172,"journal":{"name":"Physics Letters A","volume":"541 ","pages":"Article 130429"},"PeriodicalIF":2.3,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143609397","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}
Physics Letters APub Date : 2025-03-10DOI: 10.1016/j.physleta.2025.130423
Emmanuel Kengne , Ahmed Lakhssassi
{"title":"Dynamics of stochastic nonlinear waves in fractional complex media","authors":"Emmanuel Kengne , Ahmed Lakhssassi","doi":"10.1016/j.physleta.2025.130423","DOIUrl":"10.1016/j.physleta.2025.130423","url":null,"abstract":"<div><div>We consider in this work a nonlinear heat equation with cubic nonlinearity (alias real-valued stochastic Ginzburg–Landau equation) with spatiotemporal variable fractional derivatives, which is forced by a multiplicative noise in the Itô sense. Using an appropriate transformation, the model equation is reduced into a second-order nonlinear ordinary differential equation. Applying the method of Riccati equation and combining the <span><math><msup><mrow><mi>ϕ</mi></mrow><mrow><mn>4</mn></mrow></msup></math></span> expansion method with the method of Weierstrass elliptic function, exact analytical solutions of various types, including cnoidal wave solutions, solitonlike wave solutions, as well as symmetry wave solutions are presented. We show how exact analytical solutions may contribute to a deeper understanding of nonlinear behaviors, spatiotemporal correlations, and stochastic fluctuations in complex media. More precisely, we employ exact solutions to investigate graphically the effects of both fractionality and multiplicative noise on the stochastic nonlinear wave in complex fractional media whose dynamics are described by the equation model under consideration. One of the novelty of our work is that the symmetry exact wave solutions found here have not yet been presented in the context of stochastic nonlinear waves. Our results show that the variable order fractional derivatives can be used for controlling the dynamical properties of the complex systems governed by the model equation under consideration.</div></div>","PeriodicalId":20172,"journal":{"name":"Physics Letters A","volume":"542 ","pages":"Article 130423"},"PeriodicalIF":2.3,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143611563","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":"Raman spectroscopic determination of the bandgap for layered (Mo, W)-(S2, Se2)","authors":"Yixing Shi, Xuexian Yang, Yuhong Huo, Jiansheng Dong, Yonggang Huang","doi":"10.1016/j.physleta.2025.130427","DOIUrl":"10.1016/j.physleta.2025.130427","url":null,"abstract":"<div><div>Based on the bond order-length-strength mechanism and the layer number-dependent Raman shifts, the functional relation of the bandgap to the layer number was established. The equivalent coordination number, bond energy, and bandgap at the different layer numbers for transition metal dichalcogenides were quantitatively obtained. It is found that (ⅰ) with the gradual decrease in layer number, the equivalent coordination number lowers, the bond energy heightens, and the band gap increases; and (ⅱ) the differences in bond energy and ionization potential between the monolayer and bulk for TMDs dictate the strength of the layer number-dependent bandgap. The current method not only displays a new penetration into the layer number effect of bandgap, but also extends the applications of Raman shift.</div></div>","PeriodicalId":20172,"journal":{"name":"Physics Letters A","volume":"542 ","pages":"Article 130427"},"PeriodicalIF":2.3,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143611564","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}