Indian Journal of Physics最新文献

{"title":"Modeling influence of temperature and magnetic field on the density of surface states in semiconductor structures","authors":"U. I. Erkaboev,&nbsp;N. Yu. Sharibaev,&nbsp;M. G. Dadamirzaev,&nbsp;R. G. Rakhimov","doi":"10.1007/s12648-024-03360-8","DOIUrl":"10.1007/s12648-024-03360-8","url":null,"abstract":"<div><p>In this article, the physical properties of the surface of the CdS/Si(p) material under the influence of a magnetic field were studied. The dependence of the density of surface states of the p-type Si(p) semiconductor on the magnetic field and temperature has been studied. For the first time, a mathematical model has been developed to determine the temperature dependence of the density of surface states of a semiconductor under the influence of a strong magnetic field. Mathematical modeling of processes was carried out using experimental values of the continuous energy spectrum of the density of surface states, obtained at various low temperatures and strong magnetic fields, in the band gap of silicon. The possibility of calculating discrete energy levels is demonstrated.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"99 4","pages":"1281 - 1288"},"PeriodicalIF":1.6,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141947674","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":"Electromagnetic field tensor and maxwell’s equations in topological defect space-times","authors":"Meshwa Garnet Kurbah,&nbsp;Faizuddin Ahmed","doi":"10.1007/s12648-024-03373-3","DOIUrl":"10.1007/s12648-024-03373-3","url":null,"abstract":"<div><p>In this study, we explore the electromagnetic fields within the backdrop of a topological defect space-time generated by a point-like global monopole. Our investigation involves the computation of the electromagnetic field tensor and derivation of Maxwell’s equations governing the associated electric and magnetic field components. Subsequently, we extend our analysis to a cosmic string space-time, employing a similar methodology to compute the electromagnetic field tensor and Maxwell’s equations. In both scenarios, we emphasize the notable influence of topological defects on the field tensor and equations governing the electric and magnetic fields. Furthermore, our study shows that the global monopole and cosmic string parameters induces modifications in the results compared to those obtained in the Minkowski flat space. This analysis contributes to the broader understanding of how topological defects impact on the electromagnetic fields in diverse space-time geometries background.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"99 4","pages":"1401 - 1413"},"PeriodicalIF":1.6,"publicationDate":"2024-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141921372","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":"Detailed investigation of the influence of preparation method on the conduction mechanism and dielectric properties of LiNbO3 compound","authors":"K. Guithi,&nbsp;H. E. Sekrafi,&nbsp;A. Ben Jazia Kharrat,&nbsp;K. Khirouni,&nbsp;W. Boujelben","doi":"10.1007/s12648-024-03291-4","DOIUrl":"10.1007/s12648-024-03291-4","url":null,"abstract":"<div><p>In this research, we investigate the structural, electrical, and dielectric properties of the LiNbO₃ compound. Our sample was elaborated using two methods: solid–solid (sample S1) and sol–gel (sample S2). X-ray diffraction analysis with Rietveld refinement confirmed that both samples are single-phase and crystallize in the rhombohedral structure with the R3c space group.Theelectrical and dielectric properties of the LiNbO₃ compound have been studied using the impedance spectroscopy technique. DC measurements revealed semiconducting behavior for the S1 sample across the entire temperature range investigated, except for a metallic character observed between 400 and 500 K. In contrast, the S2 sample exhibited metallic behavior only between 400 and 460 K. AC data analysis indicated that the conductivity σ_AC obeys the Jonscher power law. Nyquist plots, consistent with the Cole–Cole model, allowed us to propose an equivalent circuit that incorporates the contributions of electrodes, grains, and grain boundaries to the conduction process. Dielectric measurements illustrate that the dielectric relaxation is governed by the DC conduction process. Furthermore, the high permittivity values measured support the potential application of this compound in electronic devices. These findings demonstrate the reliability of our LiNbO₃ compound for electronic device applications.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"99 2","pages":"463 - 477"},"PeriodicalIF":1.6,"publicationDate":"2024-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141920480","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":"Analysing cosmic ray density distribution using variable separable method in diverse spatial domains","authors":"Ratnakaram Raghavendra,&nbsp;Saila Kumari Anna Reddy","doi":"10.1007/s12648-024-03380-4","DOIUrl":"10.1007/s12648-024-03380-4","url":null,"abstract":"<div><p>This study employs the variable separable method to investigate the intricate dynamics of cosmic ray density distribution across diverse spatial domains. The exploration spans cylindrical, spherical, and Cartesian coordinates, delving into the effects of diffusion and velocity on cosmic ray propagation. The focal point is the evolution of cosmic ray density over time, scrutinizing the influence of parameters like diffusion coefficient, velocity, and eigenvalue. The simulations unveil compelling insights into the spatial and temporal behaviour of cosmic rays, yielding patterns that transcend coordinate systems. In the cylindrical region, the initial density distribution undergoes radial decay as cosmic rays disperse with time. In spherical coordinates, the simulation elucidates radial and angular patterns, revealing anisotropic behaviours that depend on the eigenvalue and velocity. Cartesian coordinates unfold a similar narrative, with radial decay along each axis and anisotropic tendencies along different directions. The outcomes of these simulations contribute substantively to our understanding of cosmic ray behaviour. The diffusion-driven homogenization effect becomes apparent as density gradients diminish, underscoring the integral role of diffusion in cosmic ray dynamics. By studying cosmic ray propagation in various spatial settings, this work not only elucidates fundamental principles but also lays a foundation for astrophysical applications. In essence, this research underscores the potency of the variable separable method in unravelling intricate phenomena, enabling a comprehensive exploration of cosmic ray behaviour in different environments. The insights gained from these simulations pave the way for deeper investigations into high-energy astrophysical processes and contribute to the broader understanding of cosmic ray interactions.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"99 4","pages":"1241 - 1250"},"PeriodicalIF":1.6,"publicationDate":"2024-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141920108","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":"Filaments and spirals in a noninteger dimensional universe","authors":"S. Kak","doi":"10.1007/s12648-024-03357-3","DOIUrl":"10.1007/s12648-024-03357-3","url":null,"abstract":"<div><p>The paper presents analysis showing that the earliest structures in the evolution of noninteger dimensionality in a system will be filaments and spirals. Before the dimensionality has reached 1, the structures are linear, and thereafter these filaments or threads begin to bend and fold to be in accord with fundamental scale-invariance requirements. As the evolution proceeds, threads turn into spirals in a manner that parallels phase changes in a liquid crystal. Evidence is presented that the emergence of threads and spirals is consistent with the findings in bioscience, liquid crystals, galactic center filaments, and early spiral galaxies.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"99 4","pages":"1569 - 1574"},"PeriodicalIF":1.6,"publicationDate":"2024-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141921116","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":"Developed and characterization of a novel Cd doped CeO2 nanofilm and application of methyl orange removed by photodegradation","authors":"Müge Söyleyici Çergel,&nbsp;Ersin Demir,&nbsp;Sema Kurtaran","doi":"10.1007/s12648-024-03361-7","DOIUrl":"10.1007/s12648-024-03361-7","url":null,"abstract":"<div><p>Cerium oxide (CeO₂) films doped with cadmium (Cd) were synthesized employing the ultrasonic spray pyrolysis technique (USP). The structural, surface, and optical properties of the prepared Cd-doped CeO₂ films were also investigated. All films were polycrystalline, exhibiting as cubic fluorite structure. In addition, the optical bandgap obtained using the UV data ranged from 3.23 to 3.52 eV. Cd-doped CeO₂ films exhibited Raman scattering, in which the multi-peak setting of the first optical longitudinal mode was observed, indicated the Raman shift of the characteristic peak in the ~ 461 cm⁻¹ range. In addition, the photodegradation capacities of Cd-doped CeO₂ films were investigated for the removal of pesticides that pollute human and environmental health. As a result, proposed Cd-doped CeO₂ thin films show very high (approximate 80%) photocatalytic activity for removing important pollutants, such as methyl orange dyestuff. Consequently, the CeO₂ film doped with Cd can be readily reused for five cycles without a notable alteration in photocatalytic activity.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"99 4","pages":"1289 - 1298"},"PeriodicalIF":1.6,"publicationDate":"2024-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141920168","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":"Utilizing a forced Van der Pol-Rayleigh-Helmholtz oscillator under heptamodal-frequency operations in Casimir force measurement","authors":"Cagri Yilmaz","doi":"10.1007/s12648-024-03359-1","DOIUrl":"10.1007/s12648-024-03359-1","url":null,"abstract":"<div><p>In this paper, Casimir force sensitivity is investigated by utilizing a micro-cantilever under the driving forces in heptamodal operations. A novel forced Van der Pol-Rayleigh-Helmholtz nonlinear oscillator model is developed to describe the nonlinear dynamics of the micro-cantilever which is subject to the excitation and Casimir forces simultaneously. Demonstrating the effectiveness of the heptamodal operations, single- and tetramodal-frequency excitation schemes are also applied separately to resonate the micro-cantilever at the fundamental and higher eigenmodes. The oscillation observables of the externally driven micro-cantilever are determined in the presence of the Casimir forces in the separation distance range of 200–800 nm. Remarkable variations in amplitude ratio, phase shift, and frequency shift for different effective masses of the micro-cantilever are explored for the higher eigenmodes. In the current work, the AFM micro-cantilever exhibits the amplitude response of 0.82 nm to Casimir force at the fourth eigenmode for the separation distance ranging between 200 and 300 nm. The stable frequency shifts ranging between 10³ and 10⁶ Hz are also observed at the first four eigenmodes for larger separation distances (above around 500 nm). Moreover, the maximum phase shift response of around 150 degrees at the sixth eigenmode is achieved using heptamodal-frequency excitation of the lightest micro-cantilever (3.6 × 10⁻¹² kg) at the separation distance of 200 nm. Thus, implementing heptamodal-frequency excitation schemes has considerable potential to improve the phase shift sensitivity to Casimir forces when compared with other excitation schemes. Additionally, the parameters of the nonlinear oscillator significantly determine the patterns of the time-domain sensitivities to the external forces. Correspondingly, displacements of the micro-cantilever under the driving and Casimir forces at different eigenmodes are obtained to investigate diverse system nonlinearities. Furthermore, the virial and dissipated power are also determined for different effective masses of the micro-cantilever to explain the energy dissipation process in the measurement of Casimir forces. Therefore, in the present work, the observable responses and energy quantities for particular system nonlinearities are introduced to be utilized for nanometrological applications.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"99 3","pages":"1077 - 1089"},"PeriodicalIF":1.6,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s12648-024-03359-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141924856","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":"The effects of temperature and pressure on optical properties of spherical core/shell/shell quantum dot","authors":"E. B. Al","doi":"10.1007/s12648-024-03362-6","DOIUrl":"10.1007/s12648-024-03362-6","url":null,"abstract":"<div><p>In this study, the effects of temperature and hydro-static pressure on the electronic and optical properties of the spherical core/shell/shell quantum dot structure is determined numerically. The energy eigenvalues of the system and their corresponding eigenfunctions are calculated using the diagonalization method within the framework of the effective mass approach. Then, linear, nonlinear and total intersubbands absorption coefficients and relative refractive index changes are calculated theoretically by iterative method within the framework of compact density matrix approach. With the results to be obtained from the study, it is predicted that this system can be recommended as a building block for various applications in the THz electromagnetic spectrum region.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"99 4","pages":"1299 - 1308"},"PeriodicalIF":1.6,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s12648-024-03362-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141925252","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":"Q-switched and mode-locked pulsed laser with mechanically exfoliated V2ZnC MAX saturable absorber in erbium-doped all-fibre laser","authors":"Kawther M. Musthafa,&nbsp;Azura Hamzah,&nbsp;Ooi Wei Ling,&nbsp;Ahmad Haziq Aiman Rosol,&nbsp;Norliza Mohamed,&nbsp;Sulaiman Wadi Harun","doi":"10.1007/s12648-024-03313-1","DOIUrl":"10.1007/s12648-024-03313-1","url":null,"abstract":"<div><p>Researchers have proposed diverse techniques for fabricating saturable absorbers, including aqueous acid exfoliation, evanescent coupling, and electrochemical exfoliation, with fabrication complexity and limitations that reduce saturable absorber performance and application range. We describe mechanical exfoliation and transfer as an efficient and straightforward mechanism for a MAX phase nanomaterial, <i>V</i>_<i>2</i><i>ZnC</i>, expelled into a 48.926 µm thin saturable absorber film for passively Q-switched and mode-locked all-fibre lasers, exhibiting a modulation depth of 13.16%, non-saturable absorption to be 10.21%, and saturation intensity of 4.32 kW/cm² MAX-SA; all of which demonstrated its superiority with a self-starting laser. The output laser was stable with a pulse width of 7.160 µs and a repetition rate of up to 62.23 kHz at a threshold pump power of 59.53 mW in Q-switched conditions and 346.8 ns pulse width with 963.3 kHz repetition rate at a pump power of 80.41 mW in mode-locked conditions. It is a excellent saturable absorber for the use of pulse laser production in all-fibre laser cavities because of its simple manufacturing process and outstanding optical, physical, thermal, and mechanical qualities.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"99 2","pages":"705 - 714"},"PeriodicalIF":1.6,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141923270","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":"Anisotropic star with a linear equation of state (EOS)","authors":"Rinkal Patel,&nbsp;B. S. Ratanpal,&nbsp;Ranjan Sharma","doi":"10.1007/s12648-024-03297-y","DOIUrl":"10.1007/s12648-024-03297-y","url":null,"abstract":"<div><p>A new form of the equation of state (EOS) is considered to develop a model for describing the interior of a static, spherically symmetric, compact anisotropic star. The analytic solution is obtained using the Finch and Skea ansatz for the metric potential <span>(g_{rr},)</span> with a distinct geometric interpretation for the related background spacetime. The model parameters are fixed by matching the interior solution to the Schwarzschild exterior metric over the boundary of the star, together with the requirement that the radial pressure vanishes at the boundary. Data available for the pulsar 4<i>U</i>1802030 has been utilized to analyze the physical viability of the developed model. The model is shown to be stable.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"99 2","pages":"741 - 750"},"PeriodicalIF":1.6,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141947675","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}