Indian Journal of Physics最新文献

{"title":"Features in differential cross sections and Sherman functions for electron elastic scattering from Cu, Zn, Ga, Ge, As, Se, Br and Kr atoms. I. Critical minima","authors":"V. I. Kelemen,&nbsp;E.Yu. Remeta","doi":"10.1007/s12648-026-04187-1","DOIUrl":"10.1007/s12648-026-04187-1","url":null,"abstract":"<div><p>The energies and angles of critical minima (CM) in differential cross sections (DCSs) of elastic electron scattering from atoms of the sequence from Cu up to Kr in a wide, up to 500 eV, range of collision energies, were calculated. The DCSs are characterized by the presence from one up to three minima at different angles and energies. Among these minima, some number of CM were obtained at low (in the Ramsauer-Townsend minimum region), intermediate, and high energies, as well as at low and high angles — 5 (Zn), 6 (Cu), 7 (Ge), 8 (Ga), 9 (Kr), 10 (As and Se), 11 (Br). The dependences of energies and angles of CM of these atoms on the nucleus charge Z are shown. The phase shifts which are necessary to obtain the scattering amplitudes and DCSs for above scattering process were calculated in a relativistic complex optical potential approach.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"100 12","pages":"5061 - 5084"},"PeriodicalIF":1.7,"publicationDate":"2026-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149309814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"A study of thin relativistic viscous accretion disk around a distorted Kerr black hole (DKB)","authors":"Olya Layeghi,&nbsp;Jamshid Ghanbari,&nbsp;Mahboobe Moeen Moghaddas","doi":"10.1007/s12648-026-04174-6","DOIUrl":"10.1007/s12648-026-04174-6","url":null,"abstract":"<div><p>In this paper, we analyze a thin accretion disk around a distorted Kerr black hole (DKB) within the framework of general relativity, utilizing an axisymmetric solution to the Einstein equations. We model the disk around a Kerr black hole subjected to an external gravitational field, expanded up to the quadrupole moment, and discuss the key aspects of black hole accretion disk theory. Our findings indicate that the presence of a quadrupole moment significantly influences the radiation emitted from the accretion disk. Specifically, it is observed that the sign of the quadrupole moment modifies the vertical scale height and the radial thermodynamic profiles of the disk, leading to observable variations in the peak emission and temperature gradients. Moreover, the quadrupole moment alters the geometry of the black hole’s spacetime, shifting the location of the innermost stable circular orbit (ISCO) and affecting the magnitude of the radiation flux, as well as the shape, orientation, and energy distribution of the accretion disk. This geometric alteration can also influence the efficiency of energy extraction from the black hole’s spin, which is an important factor in powering emissions from the disk. We obtain dynamical quantities around the distorted rotating black hole. Additionally, we examine how rotation influences the dynamics of the DKB and investigate the effects of varying the viscosity coefficient on the behavior of the disk.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"100 12","pages":"5507 - 5533"},"PeriodicalIF":1.7,"publicationDate":"2026-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149309525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Physical acceptability of modified Rényi holographic dark energy cosmological model in ({varvec{f}}left( {{varvec{T}},user2{mathcal{B}}} right)) theory of gravitation","authors":"V. A. Thakre,&nbsp;R. G. Kandarkar,&nbsp;A. K. Dabre","doi":"10.1007/s12648-026-04132-2","DOIUrl":"10.1007/s12648-026-04132-2","url":null,"abstract":"<div><p>In this study, we consider a modified dark energy model in the framework of <span>(fleft( {T,;mathcal{B}} right))</span> gravity theory, where <i>T</i> is the torsion scalar, and <span>(mathcal{B})</span> is the boundary term of spacetime. The model we consider is the LRS Bianchi type-I spacetime in the presence of modified Rényi holographic dark energy and pressureless matter. To solve the field equations and obtain a deterministic solution, we contemplate the simple form of <span>(fleft( {T, ;mathcal{B}} right))</span> gravity as <span>(fleft( {T,mathcal{B}} right) = alpha mathcal{B}^{beta } + T)</span> and the emergent scale factor. We calculated the cosmological parameters to study the behaviour of the Universe during cosmic evolution. The reconstructed dark energy sector has been compared with observations of BAO, SNe, and certain galaxy lensing, as well as Planck-based <span>({Lambda })</span>CDM measurements.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"100 11","pages":"4961 - 4978"},"PeriodicalIF":1.7,"publicationDate":"2026-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s12648-026-04132-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149163092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

{"title":"Integration of experimental and simulation approaches to optimize CdS buffer layers in CZTS based heterojunction solar cells","authors":"Ronaldo Roy,&nbsp;K. Kathir,&nbsp;M. C. Santhosh Kumar","doi":"10.1007/s12648-026-04127-z","DOIUrl":"10.1007/s12648-026-04127-z","url":null,"abstract":"<div><p>An integrated approach of experimentation and numerical simulation were employed to investigate the influence of cadmium sulfide (CdS) buffer layer on the performance of CZTS based heterojunction solar cells. The effect of variation in deposition time with the properties of CdS and its role as the n-layer in CdS/CZTS devices has been investigated. The deposition time of CdS thin films were varied from 30 to 120 min using a cost-effective chemical bath deposition. To investigate properties of the films XRD, SEM, EDS, Raman, and UV–visible characterisations were carried. XRD analysis confirmed the presence of cubic-phase CdS with improved crystallinity, while SEM images showed a densely packed, boulder-like morphology. Additionally, EDS confirmed a stoichiometric Cd-to-S ratio. Film thickness found to increase from 160 to 400 nm, while bandgap slightly narrowed from 2.46 to 2.40 eV. Hall measurement showed improved n-type conductivity with deposition time. Heterojunctions devices of architecture &lt; FTO/CdS/CZTS/Ag &gt; were fabricated and their junction parameters are evaluated by using I-V measurements. Further, solar cell devices of the same structure were simulated using SCAPS-1D. The CdS layer deposited for 30 min yielded the best performance, with a simulated efficiency of 17%. This investigation suggests that deposition time of CdS film is a key parameter for optimizing photovoltaic devices.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"100 11","pages":"4769 - 4781"},"PeriodicalIF":1.7,"publicationDate":"2026-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149163091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"A DFT insight of the electronic, optical, elastic, and thermoelectric properties of OsPn(_2) (Pn = P, As)","authors":"L. Chawngthu,&nbsp;L. Hima,&nbsp;R. Zosiamliana,&nbsp;L. Zuala","doi":"10.1007/s12648-026-04163-9","DOIUrl":"10.1007/s12648-026-04163-9","url":null,"abstract":"<div><p>In this study, the optoelectronic and thermoelectric properties of orthorhombic marcasite-type OsPn<span>(_2)</span> (Pn = P, As; space group Pnnm, No. 58) were systematically investigated using first-principles DFT calculations. Phonon dispersion spectra exhibit no imaginary frequencies throughout the Brillouin zone, confirming the dynamical stability of both compounds, while the fulfillment of Born stability criteria verifies their mechanical robustness. Electronic structure calculations performed within the GGA and GGA+SOC frameworks reveal indirect semiconducting behavior with narrow band gaps ranging from 0.67 to 0.86 eV. The optical response is characterized by strong light absorption, with absorption coefficients exceeding 1 <span>(times)</span> 10<span>(^{5})</span> cm<span>(^{-1})</span> across the visible and ultraviolet regions, indicating favorable optoelectronic functionality. Thermoelectric transport calculations based on the semiclassical Boltzmann approach predict excellent high-temperature performance, yielding maximum ZT values of 0.74 for OsP<span>(_2)</span> and 1.49 for OsAs<span>(_2)</span> at 1200 K. The significantly enhanced thermoelectric efficiency of OsAs<span>(_2)</span>, coupled with the strong optical absorption of both compounds, identifies OsPn<span>(_2)</span> as a promising platform for high-temperature thermoelectric and optoelectronic applications.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"100 12","pages":"5231 - 5247"},"PeriodicalIF":1.7,"publicationDate":"2026-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149310309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Influence of nonlinear conventional saturation on spatio-temporal modulational instabilities in PT-symmetric fiber Bragg grating structures","authors":"P. Mohanraj,&nbsp;R. Sivakumar,&nbsp;Ancemma Joseph,&nbsp;B. Felcia Merlin,&nbsp;Mohd. Shkir","doi":"10.1007/s12648-026-04177-3","DOIUrl":"10.1007/s12648-026-04177-3","url":null,"abstract":"<div><p>This paper is intended to present an investigation into the impact of cubic, quintic, and saturable nonlinearity on the instability in PT-symmetric fiber Bragg grating structures (FBG) with various PT-symmetry regimes. A conventional linear stability analysis identifies the modulational instability (MI) gain, where the combinatorial influence of cubic and quintic nonlinearities on MI is carefully studied in both normal and anomalous dispersion regimes. Additionally, we investigate the characteristics of MI at the bottom and top edges of the photonic band gap. The investigation highlights the importance of non-Kerr nonlinearity in relation to the MI gain. It is shown that even in the presence of PT-symmetry, one could effectively control the MI by varying the cubic, quintic, and saturable nonlinearity for various PT-symmetric regimes. The investigation revealed a range of spectral varieties, including asymmetry, symmetry, sideband spectrum, steadily increasing gain, broad spectrum, and others. We find an anomalous spectrum that is more discrete than continuous for the few physical components. The emergence of solitary waves in nonlinear episodic structures is also examined following the use of PT-symmetry.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"100 10","pages":"4353 - 4369"},"PeriodicalIF":1.7,"publicationDate":"2026-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148909655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Diffusion of colloidal particles on surfaces of droplets of Pickering emulsions and cage effect: exact theory and experimental inspiration","authors":"A. Daoudi,&nbsp;M. Benhamou,&nbsp;E. H. El Kinani","doi":"10.1007/s12648-026-04170-w","DOIUrl":"10.1007/s12648-026-04170-w","url":null,"abstract":"<div><p>This work is dedicated to a general theoretical study of the normal and anomalous diffusions of colloidal particles that move on the surfaces of droplets of oil-in-water or water-in-oil Pickering emulsions. These diffusions are caused by collisions of a target colloidal particle with molecules forming the interface between oil and water or with other colloidal particles of the same kind. Our investigation was motivated by experimental observations of these Pickering emulsions, which first state that an increase in the mass density of stabilizing colloidal particles experimentally leads to the stabilization of the droplet-size, and second, this same size decreases with increasing bulk-particle-mass density. The primary objective of our theoretical model was a quantitative study of the effect of the interface curvature on the diffusion laws. The dynamics of a target colloidal particle was studied through <i>three</i> dynamic quantities of interest, which are the mean-square-displacement (MSD), the time-diffusion-coefficient (TDC) and the velocity-autocorrelation-function (VACF). For the study, we have extracted the needed parameters by experimental fits. Our study was accomplished using Langevin Equation Theory or its generalization, solved by the instantaneous velocity of the target colloidal particle. For a normal diffusion (fast movement) that occurs at low bulk-particle-mass densities, we demonstrated the existence of <i>three</i> particle-mass density regimes for the three aforementioned dynamic quantities: an <i>underdamped regime</i>, an <i>overdamped regime</i>, and a <i>critical regime</i>. For higher bulk-particle-mass densities, however, the target colloidal particle executes rather a subdiffusion (slow movement); in this case, we demonstrated the existence of <i>three</i> time regimes: a <i>ballistic regime</i>, a <i>subdiffusive regime</i>, and a <i>saturation regime</i>. The main result is that, at large-times, MSD reaches a finite value that depends on the bulk-particle-mass density, and may be estimated experimentally. Finally, a particular attention was paid to a quantitative investigation of the cage effect, computing the stay duration of a target colloidal particle in a cage formed by its neighbors (other colloidal particles considered as mobile traps), upon the bulk-particle-mass density.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"100 12","pages":"5311 - 5325"},"PeriodicalIF":1.7,"publicationDate":"2026-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149310543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 mean step boundary model of the solar atmospheric loops and the correct derivation of the Zaitsev-Stepanov-Edwin-Roberts (ZSER) dispersion relation","authors":"Naga Varun Yelagandula","doi":"10.1007/s12648-026-04178-2","DOIUrl":"10.1007/s12648-026-04178-2","url":null,"abstract":"<div><p>Solar atmospheric loops constitute the basis of the coronal magnetic structure. Usually, the abrupt step boundary model of the magnetic flux tube is used to model these magnetized plasma loops while analyzing different wave modes exhibited by them. We prove that the abrupt step boundary model is logically self-contradictory by showing that there is a singularity in the force density at the boundary even when the flux tube is static and therefore, show that the derivation of the well-known dispersion relation of the ZSER theory for the magnetoacoustic modes using this model is incorrect. As an alternative we present a more refined model called as the mean step boundary model for the solar atmospheric loops. We prove that such a model is free from the model induced artifacts or singularities and therefore conclude that this model must be used instead of the regularly used abrupt step boundary model of the flux tubes in all the applications that are astrophysical or otherwise. As a supplement, we derive the dispersion relation of the ZSER theory in a mathematically rigorous way using this new model. </p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"100 12","pages":"5459 - 5464"},"PeriodicalIF":1.7,"publicationDate":"2026-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149310541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Band-gap reduction and electronic structure modulation in In-doped SnS2 Monolayers: a first-principles study","authors":"Hassan Zakaria Karm,&nbsp;Mujahid Eldaw Jahelnabi Mohammed,&nbsp;Rawia Abdelgani Elobaid","doi":"10.1007/s12648-026-04173-7","DOIUrl":"10.1007/s12648-026-04173-7","url":null,"abstract":"<div><p>Motivated by well-established reports that the energy band gap of two-dimensional tin disulfide (<span>({text{SnS}}_{2}))</span> systematically increases in the monolayer limit due to quantum confinement effects, this study examines the hybridization mechanisms and electronic structure modulation of <span>({text{SnS}}_{2})</span> monolayers via indium (In) substitutional doping. In contrast to earlier, broader doping studies, density functional theory (DFT) calculations using both PBE and HSE06 functionals were performed on a 54-atom supercell where one Sn atom was substituted by In (1.85% atomic concentration) to identify the underlying orbital overlap mechanisms. Projected density of states (PDOS) and electronic band structure analyses reveal that indium doping induces a controlled band-gap reduction. This modulation originates from the strong hybridization between the introduced In-s/p states and the host S-p valence states near the band edges, rather than forming isolated localized levels. Furthermore, Bader charge analysis clarifies the local charge redistribution and electronic interactions within the doped matrix. Our findings elucidate the precise electronic mechanisms of indium substitution in <span>({text{SnS}}_{2})</span> monolayers, establishing a rigorous theoretical framework for assessing its utility in specialized optoelectronic applications.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"100 12","pages":"5279 - 5287"},"PeriodicalIF":1.7,"publicationDate":"2026-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149310527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Analytic fill factor expression for double junction tandem solar cells","authors":"Neda Hasanzadeh Bishegahi,&nbsp;Abdollah Eskandarian,&nbsp;Abbas Ghadimi,&nbsp;Ali Esmaeeli","doi":"10.1007/s12648-026-04154-w","DOIUrl":"10.1007/s12648-026-04154-w","url":null,"abstract":"<div><p>We present closed form analytic formulae for the fill factor of single and double junction tandem solar cells. We start with the observation that the difference between maximum power voltage and open circuit voltage is small compared to their values. Then an explicit relation relating the maximum power voltage to the open circuit voltage is derived for the single junction (SJ) cell. Consequently, fill factor (FF) is expressed solely as a function of the open circuit voltage. Our expressions are examined against those given in literature for the SJ cell and show very good agreement. Comparing the results of our calculations against data points given in literature, the ideality factor is varied as a parameter and cumulative error is calculated. Satisfactory agreement is observed for Silicon cells with n = 1.1 and III-V compound cells with n = 1.7. The SJ derivation validates our approach which is also applied to the double junction (DJ) cells. Clearly, the complexity is increased for the DJs. Additional factors such as the photo current ratio of the sub cells enters the equations. Nevertheless, closed form expression is obtained for the FF in terms of the open circuit voltage. The prediction of our double junction formula is compared with the data points quoted in literature with ideality factor as a parameter and good agreement is obtained with n = 1.8 assuming sub-cell photo current ratio of 2:1. Having established the above parameters, our calculations are within 10% of the results quoted in literature. In fact, the agreement is better than 5% for near 90% of the cases considered.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"100 10","pages":"4271 - 4284"},"PeriodicalIF":1.7,"publicationDate":"2026-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148909812","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}