Indian Journal of Physics最新文献_第2页

Alloying enhanced structural, electronic, elastic and optical properties of CaHf1-xGexS3 (x = 0.00, 0.25, 0.50, 0.75, and 1.00) chalcogenide perovskites for Optoelectronic Applications: First Principle Study 用于光电应用的钙钛矿CaHf1-xGexS3 （x = 0.00, 0.25, 0.50, 0.75和1.00）的结构、电子、弹性和光学性能的合金化：第一性原理研究

IF 1.7 4区物理与天体物理

Indian Journal of Physics Pub Date : 2026-07-22 DOI: 10.1007/s12648-026-04124-2

Mulugetta Duressa Kassa

{"title":"Alloying enhanced structural, electronic, elastic and optical properties of CaHf1-xGexS3 (x = 0.00, 0.25, 0.50, 0.75, and 1.00) chalcogenide perovskites for Optoelectronic Applications: First Principle Study","authors":"Mulugetta Duressa Kassa","doi":"10.1007/s12648-026-04124-2","DOIUrl":"10.1007/s12648-026-04124-2","url":null,"abstract":"<div>Alloying engineering offers a powerful route to tailor the multifunctional properties of chalcogenide perovskites for optoelectronic applications. This work presents a comprehensive first-principles investigation of the structural, electronic, optical, and elastic properties of orthorhombic CaHf1-xGexS3 (x = 0.00, 0.25, 0.50, 0.75, 1.00) using density functional theory with on-site Coulomb correction (DFT + U) and density-functional perturbation theory (DFPT). All compositions preserve the orthorhombic Pnma framework, while Ge substitution induces lattice contraction and enhanced covalency. Negative formation energies and calculated Goldschmidt tolerance factors confirm both thermodynamic and structural stability across the alloy series. Electronic structure analysis revealed semiconducting behavior with band gaps tunable within the range of (1.84 - 0.59eV). While the gap generally decreases with Ge substitution, a specific electronic transition/structural variation is observed at (x=0.75). Mechanical analysis demonstrates that B-site alloying drives a transition from brittle to ductile behavior, while optical studies show good light absorption, high optical conductivity, and increased reflectivity, highlighting suitability for photovoltaics, photodetectors, and light-emitting devices. This study establishes CaHf1-xGexS3 as a versatile and designable platform for next-generation optoelectronic materials, demonstrating that controlled B-site substitution can precisely tune structural, electronic, and optical properties in sulfide perovskites.</div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"100 11","pages":"4737 - 4751"},"PeriodicalIF":1.7,"publicationDate":"2026-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149163152","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}

引用次数: 0

Synthesis, dielectric, conductivity, and impedance spectroscopy of surface modified graphene oxide: effects of frequency and thickness 表面改性氧化石墨烯的合成、介电、电导率和阻抗谱：频率和厚度的影响

IF 1.7 4区物理与天体物理

Indian Journal of Physics Pub Date : 2026-07-22 DOI: 10.1007/s12648-026-04133-1

Devendra Patel, Shyama Prasad Mahapatra

{"title":"Synthesis, dielectric, conductivity, and impedance spectroscopy of surface modified graphene oxide: effects of frequency and thickness","authors":"Devendra Patel, Shyama Prasad Mahapatra","doi":"10.1007/s12648-026-04133-1","DOIUrl":"10.1007/s12648-026-04133-1","url":null,"abstract":"<div>Graphene oxide (GO), acid-functionalized GO (GO-AC), and amine-functionalized GO (GO-AM) were synthesized and comparatively analyzed to study the effects of surface modifications and sample thickness on structural and dielectric properties. UV–Visible spectra showed redshifts upon functionalization, while FTIR confirmed the presence of carboxyl and amine groups. XRD revealed decreasing crystallite sizes, and Raman analysis indicated increasing disorder from GO to GO-AC and to GO-AM. EDX verified surface modifications, showing varied C/O ratios. Dielectric studies revealed a shift of loss tangent to lower frequencies with increasing thickness. GO-AM exhibited the highest capacitance, dielectric permittivity, dielectric loss and electrical conductivity, while GO and GO-AC showed moderate and suppressed dielectric response respectively. Cole–Cole and modulus analyses indicated reasonable relaxation in GO, restricted polarization in GO-AC, and strong dielectric dispersion in GO-AM. Impedance and Nyquist plots confirmed improved charge transport in GO-AM and higher resistivity in GO-AC. Overall, GO-AM exhibited superior dielectric and conductive performance, making it a promising material for energy storage and electronic applications.</div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"100 11","pages":"4573 - 4589"},"PeriodicalIF":1.7,"publicationDate":"2026-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149163133","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}

引用次数: 0

Cosmological dynamics of Sharma-Mittal Holographic Dark Energy in Brans–Dicke gravity Brans-Dicke引力中Sharma-Mittal全息暗能量的宇宙学动力学

IF 1.7 4区物理与天体物理

Indian Journal of Physics Pub Date : 2026-07-22 DOI: 10.1007/s12648-026-04137-x

R. Sathibabu, K. V. S. Sireesha

{"title":"Cosmological dynamics of Sharma-Mittal Holographic Dark Energy in Brans–Dicke gravity","authors":"R. Sathibabu, K. V. S. Sireesha","doi":"10.1007/s12648-026-04137-x","DOIUrl":"10.1007/s12648-026-04137-x","url":null,"abstract":"<div>In the framework of Brans–Dicke(BD) theory, we have considered a Bianchi type (BT)–III anisotropic spacetime with a cosmological model consisting of Sharma-Mittal Holographic Dark Energy (SMHDE) and pressureless matter. We analyse the temporal evolution of important parameters for the deceleration parameter, the Equation of State (EoS) parameter, state finder diagnostics, skewness, scalar field, and the squared speed of sound. We observe a smooth transition from an early decelerating epoch to a late accelerating epoch. The EoS parameter evolves from a quintessence-like phase to a phantom regime at late times. Moreover, the scalar field and matter density show negligible values at the early times and increase dramatically towards later times with the role of Sharma-Mittal entropy corrections. Compared with the (Lambda)CDM model, the SMHDE setup incorporates the main behaviour of late-time acceleration into the (Lambda)CDM model and, in addition shows dynamic dark energy, phantom crossing, and entropy-related correction. These results indicate that this SMHDE model in BD gravity is theoretically extended and observationally viable as compared to the standard (Lambda)CDM cosmology. Additionally, we investigate the classical stability of the models by analysing the squared sound speed parameter.</div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"100 11","pages":"4993 - 5008"},"PeriodicalIF":1.7,"publicationDate":"2026-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149162897","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}

引用次数: 0

Dynamic stress response of a transversely isotropic rock layer with parabolic irregularity under moving load: a perturbation approach 移动荷载作用下具有抛物状不规则的横向各向同性岩层的动应力响应：摄动方法

IF 1.7 4区物理与天体物理

Indian Journal of Physics Pub Date : 2026-07-21 DOI: 10.1007/s12648-026-04129-x

Manoj Kumar Singh, Juhi Baroi, Soniya Chaudhary, Amit Kumar Rahul, Ram Kumar, Kamlesh Kumar Pankaj

{"title":"Dynamic stress response of a transversely isotropic rock layer with parabolic irregularity under moving load: a perturbation approach","authors":"Manoj Kumar Singh, Juhi Baroi, Soniya Chaudhary, Amit Kumar Rahul, Ram Kumar, Kamlesh Kumar Pankaj","doi":"10.1007/s12648-026-04129-x","DOIUrl":"10.1007/s12648-026-04129-x","url":null,"abstract":"<div>This study investigates the stress generated in a stationary transversely isotropic rock medium resting on the ocean floor and subjected to a moving load. The upper rock layer incorporates a parabolic surface irregularity, and a comparative analysis is performed for three scenarios: parabolic, rectangular, and no surface irregularity. To solve the resulting nonlinear second-order partial differential equation governing the displacement field, Fourier Integral Transform Method is employed due to its effectiveness in handling such problems. The analysis reveals that the incremental normal stresses vanish directly beneath the boundary, while the incremental shear stresses attain their maximum at the same point. Because the boundary surface is irregular, a perturbation method is employed to obtain a linearized approximation of the governing equations. Since the perturbation parameter (epsilon) is assumed to be very small (left( { in < < 1} right)), terms involving higher powers of (epsilon) are neglected, and only first-order terms are considered in the analysis. A detailed parametric study is conducted to evaluate the influence of various factors, including layer thickness, depth, type of surface irregularity, and heterogeneity parameters, on the shear and normal stresses. Exponential heterogeneity is assumed in the rock medium, and comparisons are made between parabolic and rectangular heterogeneity profiles using graphical illustrations. The shear stress is computed numerically, and the results are presented graphically to support the findings. Additional insights are provided regarding the significant roles of the depth factor and the frictional coefficient in stress behavior in both media.</div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"100 10","pages":"4303 - 4319"},"PeriodicalIF":1.7,"publicationDate":"2026-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148909805","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}

引用次数: 0

Holographic dark energy with quantum decoherence: a conservative cosmological model 具有量子退相干的全息暗能量：一个保守的宇宙学模型

IF 1.7 4区物理与天体物理

Indian Journal of Physics Pub Date : 2026-07-21 DOI: 10.1007/s12648-026-04135-z

Mahgoub A. Salih

{"title":"Holographic dark energy with quantum decoherence: a conservative cosmological model","authors":"Mahgoub A. Salih","doi":"10.1007/s12648-026-04135-z","DOIUrl":"10.1007/s12648-026-04135-z","url":null,"abstract":"<div>We present Holographic Information Cosmology, a conservative extension of the standard cosmological model in which dark energy emerges from holographic entropy modulated by quantum decoherence, while dark matter remains cold dark matter (CDM) with a decoherence-modified growth function. The universe originates via quantum tunneling from nothing, providing a semiclassical mechanism for singularity avoidance within the WKB approximation. HIC introduces a single additional parameter, the decoherence rate (Gamma _D sim 10^{-18}) s(^{-1}), which is derived from quantum-gravity considerations and whose value coincides with the Hubble rate, thereby setting the timescale for dark-energy domination. Using a custom Julia-based Boltzmann solver validated against CAMB to (0.05%) precision, we perform Fisher-matrix forecasts with Planck 2018, DESI DR1, and DES Year 3 data under explicitly defined flat priors. The analysis yields realistic uncertainties: (sigma (Gamma _D)/Gamma _D approx 25%), (sigma (Omega _m) approx 0.02), and (sigma (H_0) approx 1.2) km/s/Mpc. HIC reproduces the goodness-of-fit of (Lambda)CDM ((Delta chi ^2 approx 0)) and yields a modest Bayes factor, (ln B approx 0.5 pm 0.3), reflecting the penalty for the extra parameter. The model predicts distinctive signatures: enhanced CMB (mu)-distortions ((mu sim 1.8 times 10^{-8})), scale-dependent primordial non-Gaussianity ((f_{text {NL}} sim 0.18)), and a (0.7%) enhancement of structure growth detectable at (sim 2.3sigma) by LSST Y10. HIC thus grounds dark energy in fundamental quantum-mechanical principles while retaining the empirical success of (Lambda)CDM.</div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"100 11","pages":"4979 - 4992"},"PeriodicalIF":1.7,"publicationDate":"2026-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149162955","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}

引用次数: 0

Photothermal wave propagation in a stochastic two-temperature magneto-electro conductive medium 光热波在随机双温磁导介质中的传播

IF 1.7 4区物理与天体物理

Indian Journal of Physics Pub Date : 2026-07-17 DOI: 10.1007/s12648-026-04122-4

E. S. Elidy, Abdelaala Ahmed, Shreen El-Sapa, Alaa A. El-Bary, Khaled Lotfy

{"title":"Photothermal wave propagation in a stochastic two-temperature magneto-electro conductive medium","authors":"E. S. Elidy, Abdelaala Ahmed, Shreen El-Sapa, Alaa A. El-Bary, Khaled Lotfy","doi":"10.1007/s12648-026-04122-4","DOIUrl":"10.1007/s12648-026-04122-4","url":null,"abstract":"<div>This study investigates the stochastic propagation of thermoelastic waves in a photothermally excited semiconducting medium under the influence of a magnetic field and variable electrical conductivity. A two-temperature generalized thermoelastic model is employed to account for both conductive and thermodynamic temperatures, enhancing the accuracy of thermal wave predictions. The Laplace transform techniques are used to derive analytical expressions for displacement, stress, temperature, and carrier density. Stochastic effects are incorporated through random boundary conditions and white noise excitation, transforming the deterministic model into a probabilistic framework. The influence of magnetic fields and conductivity variations is examined, revealing their significant impact on wave dispersion, energy dissipation, and stochastic variance of physical fields. Numerical simulations using silicon parameters confirm that increased conductivity and magnetic intensity suppress wave amplitudes and sharpen gradients. These findings provide critical insights for the design of optoelectronic and magneto-thermoelastic devices subjected to rapid photothermal excitation.</div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"100 11","pages":"5009 - 5027"},"PeriodicalIF":1.7,"publicationDate":"2026-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149163061","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}

引用次数: 0

Size-dependent optical and electrical properties of PbS and ZnO nanostructures: a comparative theoretical study PbS和ZnO纳米结构尺寸相关的光学和电学性质：比较理论研究

IF 1.7 4区物理与天体物理

Indian Journal of Physics Pub Date : 2026-07-16 DOI: 10.1007/s12648-026-04139-9

Rand N. Khalaf, Saeed Naif Turki Al-Rashid

{"title":"Size-dependent optical and electrical properties of PbS and ZnO nanostructures: a comparative theoretical study","authors":"Rand N. Khalaf, Saeed Naif Turki Al-Rashid","doi":"10.1007/s12648-026-04139-9","DOIUrl":"10.1007/s12648-026-04139-9","url":null,"abstract":"<div>Size-dependent optical and electrical properties of semiconductor nanostructures are governed by quantum confinement and strongly influenced by intrinsic electronic structure. This work presents a systematic theoretical study of PbS and ZnO nanostructures with the objective of comparing narrow and wide band gap semiconductors in a single framework. The size dependence of band gap, refractive index, optical dielectric constant, carrier concentration, and electrical conductivity is assessed using three complementary theoretical models: the Brus model, the Hyperbolic model, and the Cohesive Energy model. The obtained results are critically compared with existing experimental and theoretical studies to determine the applicability of the models in various confinement regimes. The findings demonstrate that quantum confinement effects are more pronounced in PbS, resulting in strong band gap widening and high optical constants at small particle sizes, compared with ZnO, which shows weaker size dependence and a rapid approach to bulk behavior. Strong confinement in PbS is well described by the Brus model, whereas the Hyperbolic model better describes the bulk-convergence behavior of ZnO with general agreement in larger size regimes. Analysis of electrical transport indicates that carrier concentration and conductivity are strongly model-dependent. PbS shows strong confinement-induced suppression at very small sizes followed by rapid conductivity enhancement with increasing particle diameter, whereas ZnO exhibits smoother conductivity growth and saturation behavior associated with its intrinsic n-type character. In general, this paper establishes that no single model describes all size-dependent properties and highlights the significance of choosing theoretical approaches according to the type of material, size regime, and desired physical property.</div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"100 11","pages":"4687 - 4701"},"PeriodicalIF":1.7,"publicationDate":"2026-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149163131","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}

引用次数: 0

Raman study of phase transitions in the ruthenocene crystal at high pressure 高压下钌新世晶体相变的拉曼研究

IF 1.7 4区物理与天体物理

Indian Journal of Physics Pub Date : 2026-07-15 DOI: 10.1007/s12648-026-04140-2

K. P. Meletov

引用次数: 0

Exploring flavours with bottomonia candidates 与底onia候选人一起探索味道

IF 1.7 4区物理与天体物理

Indian Journal of Physics Pub Date : 2026-07-14 DOI: 10.1007/s12648-026-04136-y

Swagata Biswas, Debasish Das

引用次数: 0

Unveiling structural, electromagnetic, and phonon stability in a double perovskite ferroelectrics compound: a computational perspective 揭示双钙钛矿铁电化合物的结构、电磁和声子稳定性：计算视角

IF 1.7 4区物理与天体物理

Indian Journal of Physics Pub Date : 2026-07-14 DOI: 10.1007/s12648-026-04126-0

Slimane Haid, Samir Bentata, Bouabdalah Bouadjemi, Mohammed Houari, Mohamed Matougui, Tayeb Lantri, Zoubir Aziz

{"title":"Unveiling structural, electromagnetic, and phonon stability in a double perovskite ferroelectrics compound: a computational perspective","authors":"Slimane Haid, Samir Bentata, Bouabdalah Bouadjemi, Mohammed Houari, Mohamed Matougui, Tayeb Lantri, Zoubir Aziz","doi":"10.1007/s12648-026-04126-0","DOIUrl":"10.1007/s12648-026-04126-0","url":null,"abstract":"<div>\u0000 \u0000 This numerical work focuses on studying the electronic, structural, elastic, magnetic, and thermoelectric properties of Ba2GdMoO6 and the mechanical and thermal stability of this double perovskite oxide compound as well. This study has been numerically explored using Density Functional Theory (DFT) as implemented in the WIEN2k code. Respectively, for the structural and electronics properties, we have adopted the GGA, GGA + U, and mBJ-GGA + U functional as exchange–correlation approximations, as embedded in the WIEN2k code. It was explored how well this material performed thermoelectrically using Boltzmann transport theory. As a result, positive phonon spectra signify the dynamical stability of the studied cubic material, Ba2GdMoO6. During the energy minimization versus volume procedure, this compound has a stable ferromagnetic ground state. According to electronic results, Ba2GdMoO6 exhibits a half-metallic behavior, having total integer magnetic moments of 8.00 μB. Indirect band gap equal to 3.547 eV for Ba2GdMoO6 cubic material, located at ΓV—XC direction. An analysis of the thermoelectric properties was performed using the semi-classical Boltzmann transport approach. Furthermore, this compound has a merit figure (ZT) with a high value, close to unity at room temperature, and a high Seebeck coefficient (S) value. This in-depth analysis underscores the high relevance and practical utility of the examined compound, Ba2GdMoO6, for modern electronics, data storage, optoelectronics, and spintronics, and especially for energy conversion and acquisition through thermoelectric devices to meet socioeconomic demands.\u0000 </div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"100 11","pages":"4753 - 4767"},"PeriodicalIF":1.7,"publicationDate":"2026-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149163105","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}

引用次数: 0