International Journal of Modern Physics B最新文献

{"title":"Double stratification impacts on MHD flow of micropolar nanofluid over a stretching surface inserted in porous medium","authors":"M. I. Anwar, M. Ali, H. B. Lanjwani, S. A. Shehzad","doi":"10.1142/s0217979224503594","DOIUrl":"https://doi.org/10.1142/s0217979224503594","url":null,"abstract":"A comprehensive analysis of double stratification impacts on the MHD flow of a nanofluid produced by a porous stretching sheet has been conducted by using a numerical approach. The convective boundary conditions (CBCs) and Newtonian heating (NH) cases have been particularly considered in this problem. The governing equations defined in partial differential equations (PDEs) form are converted into ordinary differential equations (ODEs) by using appropriate transformations to meet the requirement of the used numerical method which is bvp4c in the MATLAB software package. Moreover, the numerical findings of the ODEs are displayed via graphical and tabular forms. The impacts of different flow parameters used in particular problem are discussed for the profiles of the velocity, temperature and concentration of micropolar nanofluid along the values of coefficient of skin-friction [Formula: see text], Nusselt number [Formula: see text], the Sherwood number [Formula: see text] and in relation with the variation parameters in general, CBC and NH are calculated to get a clear insight into the flow situation. Some of the findings show that the skin friction increases by increase in magnetic, permeability and material parameters in all cases but the skin friction is reduced by increasing the thermophoresis parameter for CBC and NH cases, respectively. Microrotation profile decreases when material parameter increases, whereas microrotation profiles enhance with increase of the magnetic field and porosity of porous medium.","PeriodicalId":14108,"journal":{"name":"International Journal of Modern Physics B","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135200786","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":"Tuning the electronic structure and absorption spectrum of ZnTe/ZnS heterojunctions by selective doping with yttrium: A first-principle study","authors":"Haonan Li, Cong Li, Hailiang Huang, Guodong Hao, Fei Wang","doi":"10.1142/s021797922450365x","DOIUrl":"https://doi.org/10.1142/s021797922450365x","url":null,"abstract":"This paper systematically investigates the electronic structure and optical properties of zinc-blende ZnTe, ZnS systems, ZnTe/ZnS heterojunctions, and Y-doped ZnTe/ZnS heterostructions using the generalized gradient approximation (GGA) method under the density functional theory (DFT) framework. The results show that compared to the single-component ZnTe or ZnS systems, the ZnTe/ZnS heterojunction has a smaller bandgap width and undergoes a redshift in the absorption spectrum, which is favorable for more valence band electrons to be excited by light and transition to the conduction band, thereby enhancing the optoelectronic properties of the material. After Y-doping in the ZnTe/ZnS heterojunction system, when the doping concentration is between 1.56[Formula: see text]at% and 4.69[Formula: see text]at%, doping Y in the ZnS layer would result in the lowest energy formation of the system. Therefore, it can be inferred that in experiments, if the doping concentration is increased beyond this range, Y atoms are more likely to be arranged in the ZnS layer. Compared with the pure ZnTe/ZnS heterojunction system, increasing the Y doping concentration results in a wider bandgap and a more prominent blue shift in the absorption spectrum. Therefore, it is possible to adjust the bandgap of the heterojunction by changing the doping concentration to fabricate heterojunction device with different photoelectric effects and luminescence properties.","PeriodicalId":14108,"journal":{"name":"International Journal of Modern Physics B","volume":"2015 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135200140","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":"Effects of deformation on Zn atom-adsorbed borophene","authors":"Qing Su, Ying Wang, Xuewen Gao, Guili Liu, Guoying Zhang","doi":"10.1142/s0217979224503570","DOIUrl":"https://doi.org/10.1142/s0217979224503570","url":null,"abstract":"The effects of tensile and compressive deformation on the structural stability, electronic structure and optical properties of the Zn atom-adsorbed borophene system, which are exhibited by reflectivity, absorption coefficient, bandgap and adsorption energy, were studied using the first-principles calculations based on density functional theory (DFT). The borophene planes were found to be distorted following Zn atom adsorption. The adsorption energy calculations show that the stability decreases both under tensile and compressive strains. When tensile and compressive loading increase to 5%, respectively, the system loses the stability and the ability of adsorbing Zn atoms on borophene. The band structure and density of states analysis show that the band structure of borophene is changed by the Zn atom adsorption, with a band overlap near the Fermi level and more impurity energy levels in the conduction band. The hybridization is formed between Zn atom and borophene in the range of –12[Formula: see text]eV to 6[Formula: see text]eV, with the s and p orbitals both contributing to the conduction and valence bands, but p orbitals make a larger contribution to the total density of states than s orbitals. Studies of optical properties have shown that tensile and compressive strains both increase the dielectric constant of the adsorbed system, with compressive strains causing a redshift in the major peaks of the real and imaginary parts of the spectrum. The tensile strain has little effect on the absorption coefficient and reflectance of the borophene. As the compressive strain increases, the peak absorption coefficient of the adsorbed system is shifted to the blue and the peak reflectance is redshifted.","PeriodicalId":14108,"journal":{"name":"International Journal of Modern Physics B","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135200146","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":"Study of superconductivity of Li-doped Fe (Se0.5Te0.5) polycrystalline bulk samples","authors":"W. He, X. F. Bai, J. H. Yang, J. Zhang, K. Zhao, C. Liang, F. G. Cai, Z. M. Hu, X. S. Yang, Y. Zhao","doi":"10.1142/s0217979224503600","DOIUrl":"https://doi.org/10.1142/s0217979224503600","url":null,"abstract":"Fe(Se/Te) family compounds are very important among iron-based superconductors. To explore the modification of their physical properties, Li-doped FeSe[Formula: see text]Te[Formula: see text] polycrystalline samples were prepared by using sintering method with metal Li as the dopant. X-ray diffraction (XRD) and Raman scattering indicated that the lattice parameter c and Raman peaks change systematically with increasing Li content, suggesting Li atoms have entered the lattice. Magnetization and electrical transport measurements showed the type-II superconductor behavior. The upper critical field increased with increasing Li doping concentration, while the coherence length decreased with increasing dopant concentration. Li-doping generally improved the superconductivity, including the uniformity of superconducting contents. The thermally activated flux-flow (TAFF) activation energy also increased with increasing dopant concentration. The critical current densities were measured and the flux pinning mechanism and its change with doping were analyzed.","PeriodicalId":14108,"journal":{"name":"International Journal of Modern Physics B","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135966254","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":"Tailoring magnesium-based hydrides as potential and reversible materials for solid-state hydrogen storage: A first-principles study","authors":"Shoaib Muhammad, G. Murtaza, Abida Azam, H. H. Raza, R. M. Arif Khalil, Muhammad Iqbal Hussain, M. Waqas Iqbal","doi":"10.1142/s0217979224503582","DOIUrl":"https://doi.org/10.1142/s0217979224503582","url":null,"abstract":"Hydrogen is a promising candidate for green energy sources for future endeavors because of its abundance on Earth. Although its storage is a major challenge for the researchers of this era because of its unsafe and highly explosive nature. The structural, optoelectronic, thermoelectric, vibrational, thermodynamic properties and hydrogen storage capacity of XMgH 3 ([Formula: see text], Ba) are carried out by using the full potential linearized augmented plane wave (FP-LAPW) method in the DFT framework. The theoretical study about these magnesium-based metal hydride perovskites, i.e., SrMgH 3 and BaMgH 3 , declares them structurally stable compounds in space group Pm-3m. The optimization graph for SrMgH 3 and BaMgH 3 reflects the lowest ground state energy, i.e., −6759[Formula: see text]Ry and −16683[Formula: see text]Ry, respectively. Comparatively, BaMgH 3 seems to be more stable. The electronic band structures and density of states declare them pure metallic due to zero band gap and overlapping of electronic states of the valence and the conduction bands. The electrical conductivity of BaMgH3 increases up to [Formula: see text] and thermal conductivity [Formula: see text] in the temperature range 100[Formula: see text]K to 1000[Formula: see text]K revealing the good metallic character of BaMgH 3 . The optical analysis portrays the absorption of compounds in the visible range along with valance shell electrons to the weak bond of hydrogen and dissociates hydrogen molecules at a certain intensity of light. BaMgH 3 compound shows minimum scattering and maximum absorption of light in the visible region up to 3[Formula: see text]eV. The reflectivity peaks in the visible region 3.0[Formula: see text]eV show that 40% of light energy is absorbed due to the opaque nature of BaMgH 3 . Both these compounds are declared thermodynamically stable due to negative free energy such as −1.20[Formula: see text]eV for SrMgH 3 and −1.50[Formula: see text]eV energy for BaMgH 3 at 1000[Formula: see text]K, respectively. Moreover, the three acoustic modes showing zero imaginary phonon frequencies at [Formula: see text] symmetry points predict these compounds’ structural and thermodynamical stability. The gravimetric hydrogen storage concentration of SrMgH 3 and BaMgH 3 is determined as 2.637% and 1.836%, respectively.","PeriodicalId":14108,"journal":{"name":"International Journal of Modern Physics B","volume":"794 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136098701","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":"Exploring the electronic transport, magnetic, and optical properties of strongly correlated systems: A numerical analytical continuation approach","authors":"R. K. Rai, G. C. Kaphle, R. B. Ray, O. P. Niraula","doi":"10.1142/s0217979224503417","DOIUrl":"https://doi.org/10.1142/s0217979224503417","url":null,"abstract":"The electronic, magnetic and optical properties of the double perovskites Ca 2 NiOsO 6 and Fe-doped derivative were calculated using the full potential linearized augmented plane wave technique through the GGA + U with PBE exchange correlation functionals. The calculations show that both of the systems are half-metallic with Fe-doped system as a ferromagnet, whereas the undoped system shows the ferrimagnetic ordering. Additionally, the study is extended for calculating the Mott parameters through dynamical mean field theory (DMFT) with the maximum entropy model (MEM). It is found that the MIT model parameters (U, [Formula: see text]) for Ca 2 NiOsO 6 and Ca 2 Fe[Formula: see text]Ni[Formula: see text]OsO 6 systems are (5.7[Formula: see text]eV, 6.0[Formula: see text](eV)[Formula: see text]) and (6.0[Formula: see text]eV, 6.0[Formula: see text](eV)[Formula: see text]), respectively. Furthermore, the calculations agree with optical Drude peak analysis. The optical conductivity, reflectivity, absorptivity, ELOSS function, dielectric function refractive index and sum-rule are also explored in relation to the photoinduced behaviors of the materials.","PeriodicalId":14108,"journal":{"name":"International Journal of Modern Physics B","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136237116","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":"Effects of Dzyaloshinskii–Moriya interactions on dipole-exchange spin waves in finite-length ferromagnetic chains","authors":"Bushra Hussain, Michael G. Cottam","doi":"10.1142/s0217979224503545","DOIUrl":"https://doi.org/10.1142/s0217979224503545","url":null,"abstract":"A spin-wave theory that includes the antisymmetric Dzyaloshinskii–Moriya exchange interactions and long-range dipole–dipole interactions, in addition to the Heisenberg bilinear exchange and the applied magnetic field, is presented for finite-length ferromagnetic spin chains. It is found that three different physical situations arise, depending on the direction chosen in this geometry for the axial vector of the Dzyaloshinskii–Moriya interactions. In some cases this leads to a tilting of the equilibrium orientations near the ends of the chain due to interfacial effects and with consequential effects on the spectrum of discrete dipole-exchange spin waves. When variations are introduced for the dominant bilinear exchange interactions at the ends of the spin chain, it is shown that localized spin waves with spatial decay characteristics may occur.","PeriodicalId":14108,"journal":{"name":"International Journal of Modern Physics B","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136237126","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 new type of supercontinuum generation in hexagonal lattice C₆H₆-core PCF with broadband and low-power pump","authors":"Bao Tran Le Tran, Lanh Chu Van","doi":"10.1142/s0217979224503533","DOIUrl":"https://doi.org/10.1142/s0217979224503533","url":null,"abstract":"Most of the spectral bandwidths of previous publications are still limited by high input powers making them economically less than ideal. By using a benzene core (C 6 H 6 ) photonic crystal fiber (PCF) as a new supercontinuum (SC) light source, it is possible to achieve a very large spectral broadening with hundreds of times lower peak power. Due to the change in the diameter of air holes in the first ring near the core, near-zero flattened dispersion, high nonlinearity and small attenuation can be achieved for spectral broadening. The structural geometries of two C 6 H 6 -PCFs are optimized to generate wide SC at low input energy. The SC spectrum produced in 1[Formula: see text]cm long of all dispersion fiber extends from a part of visible light to the near-infrared range at 1.3[Formula: see text][Formula: see text]m wavelength and a small pulse energy of 18[Formula: see text]pJ (or 450[Formula: see text]W of electrical input). The second PCF shows wide soliton-induced SC from 0.8 to 4.2[Formula: see text][Formula: see text]m with 71[Formula: see text]pJ pulse energy (or input power approximately 790[Formula: see text]W) at 1.5[Formula: see text][Formula: see text]m wavelength within a fiber of 12[Formula: see text]cm. The proposed structures have the potential to become a new class of microstructured optical fibers for low-cost, broad-spectrum SC generation.","PeriodicalId":14108,"journal":{"name":"International Journal of Modern Physics B","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136237118","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":"Tunable electronic and magnetic properties of 3d transition metal ion-doped monolayer graphitic-ZnO: An <i>ab-initio</i> calculation","authors":"Sulagna Ghosh, Sudipta Moshat, Dirtha Sanyal","doi":"10.1142/s0217979224503478","DOIUrl":"https://doi.org/10.1142/s0217979224503478","url":null,"abstract":"Electronic and magnetic properties of transition metal (TM) ion-doped monolayer zinc oxide (ML-ZnO) have been analyzed using ab-initio calculations in the frame work of density functional theory. Spin–spin interaction study reveals that Cr, Mn, Fe and Cu doped at Zn site of ML-ZnO show stable ferromagnetic ordering along with the half-metallic behavior for most of the cases. The electronic and magnetic properties of the pristine system can also be modified by using co-doping. 3d orbital electrons of the dopants are primarily responsible for the origin of magnetic moment and the remaining part comes from the 3d and 2p orbital electrons of Zn and O atoms, respectively. Moreover, the magnetic ordering in Fe-doped ML-ZnO can change with the doping distance between the dopants.","PeriodicalId":14108,"journal":{"name":"International Journal of Modern Physics B","volume":"187 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136310084","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":"Optimization of mixed cation organic–inorganic lead halide perovskite solar cell performance","authors":"None Ritu, None Gagandeep, Ramesh Kumar, Fakir Chand","doi":"10.1142/s0217979224503612","DOIUrl":"https://doi.org/10.1142/s0217979224503612","url":null,"abstract":"In this paper, the experimentally studied perovskite solar cell structure, ITO/SnO 2 /(FAPbI 3 )[Formula: see text] (MAPbBr[Formula: see text]Cl y ) x /Spiro-OMeTAD/Au, is considered as our primary cell structure. The Solar Cell Capacitance Simulator is used to investigate the cell performance. The cell performance is obtained after optimizing the influence of layer thickness (open circuit [Formula: see text][Formula: see text]V, short circuit [Formula: see text][Formula: see text]mA/cm 2 , fill [Formula: see text]%, power conversion [Formula: see text]%). In addition, various inorganic hole transporting layers are incorporated in place of Spiro-OMeTAD to improve cell stability and performance. Finally, with an open circuit [Formula: see text][Formula: see text]V, a short circuit [Formula: see text][Formula: see text]mA/cm 2 , a fill [Formula: see text]%, and a power conversion efficiency = 19.55%, the optimized cell structure i.e., ITO/SnO 2 /(FAPbI 3 )[Formula: see text](MAPbBr[Formula: see text]Cl y ) x /CulnSe 2 /Au, performs better. The cell performance is examined in relation to defect density in the absorber layer and at the layer interface. The primary cell results are also validated with the existing experimental results in the literature. This research will pave the way for the development of highly efficient mix-cation perovskite solar cells.","PeriodicalId":14108,"journal":{"name":"International Journal of Modern Physics B","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136310094","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}