International Journal of Modern Physics B最新文献

{"title":"The structural, magnetic and electrical properties of zinc-doped orthorhombic calcium ferrite nanoparticles: Memory device and high-frequency applications","authors":"R. Umashankara Raja, H. C. Manjunatha, Y. S. Vidya, R. Munirathnam, K. M. Rajashekara, S. Manjunatha, M. Priyanka, E. Krishnakanth","doi":"10.1142/s0217979225500419","DOIUrl":"https://doi.org/10.1142/s0217979225500419","url":null,"abstract":"<p>Calcium ferrite nanoparticles (NPs), doped with Zinc in the range of 10–50<span><math altimg=\"eq-00001.gif\" display=\"inline\" overflow=\"scroll\"><mspace width=\".17em\"></mspace></math></span><span></span>mol%, were synthesized through a solution combustion method using citrus Limon extract as a reducing agent, followed by calcination at 500^∘C. The synthesized samples are characterized with different techniques. Bragg reflections confirmed the formation of orthorhombic crystal structure. The shifting of the peak toward higher angle side is observed with increase in the dopant concentration. The surface exhibited irregular shapes and sized NPs with pores and voids in their morphology. The direct energy band gap increases from 2.91 to 2.97<span><math altimg=\"eq-00002.gif\" display=\"inline\" overflow=\"scroll\"><mspace width=\".17em\"></mspace></math></span><span></span>eV with increase in Zinc concentration. Further, magnetic and dielectric properties were carried out to know their importance in the high-frequency devices. Magnetic parameters, such as saturation magnetization (M_<i>s</i>), remanence (M_<i>r</i>), and coercivity (H_<i>c</i>) values, are discussed. M_<i>s</i>, M_<i>r</i> and H_<i>c</i> increase with increase in dopant concentration upto 30<span><math altimg=\"eq-00003.gif\" display=\"inline\" overflow=\"scroll\"><mspace width=\".17em\"></mspace></math></span><span></span>mol% and thereafter decreases. The dielectric studies revealed a decreasing dielectric constant from 2.98 to 1.84 as the dopant concentration increased. These findings suggest the potential use of these samples in memory devices and high-frequency applications.</p>","PeriodicalId":14108,"journal":{"name":"International Journal of Modern Physics B","volume":"114 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140168643","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":"Transient magnetohydrodynamic heat and mass transfer analysis of chemically reacting fluid flow over oscillatory permeable media","authors":"Ashirbad Kumar Rath, Itishree Nayak, Sukanya Padhi","doi":"10.1142/s0217979225500316","DOIUrl":"https://doi.org/10.1142/s0217979225500316","url":null,"abstract":"<p>This study focuses on the numerical observation of the convective motion of chemically active magnetohydrodynamic (MHD) fluid through a vertically oriented permeable medium, incorporating variations in mass and heat transfer. The fluid type is assumed to be incompressible, chemically strongly ionized and viscous with some mass infusibility. The model associated with this problem is solved by a highly stable Implicit Finite Difference Method (IFDM). The method is used for small and large deflection of the physical parameters, which results in a noticeable fluid flow behavior. Numerical configuration is graphically depicted to scrutinize the fluid behavior. The momentum, energy, concentration diffusion, skin friction, Nusselt number and Sherwood number are investigated for numerous factors such as magnetic field, permeability and chemical reaction rate. The current study unveils significant findings, demonstrating that a heightened rate of chemical reaction in the presence of magnetic effects, coupled with specific porosity, diminishes ionization energy, resulting in a concurrent decrease in the concentration and momentum profiles of the fluid flow. The rise in the viscous diffusion rate is attributed to escalating values of the Schmidt number, causing an augmentation in dynamic viscosity and consequently resulting in an overall reduction in the momentum of the fluid flow.</p>","PeriodicalId":14108,"journal":{"name":"International Journal of Modern Physics B","volume":"64 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140168634","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":"Design and optimization of high-performance eco-friendly perovskite solar cells: Utilizing FAMASnGeI3 and CsGeI3 as absorbers and tuning HTL and interface parameters","authors":"Pritam Kumar, Brajendra Singh Sengar, Amitesh Kumar","doi":"10.1142/s0217979225500341","DOIUrl":"https://doi.org/10.1142/s0217979225500341","url":null,"abstract":"<p>In this work, several designs of lead-based and lead-free perovskite solar cells (PSCs) have been developed and investigated. For the proposed designs, CH₃NH₃PbI₃ (lead-based), FAMASnGeI₃, and CsGeI₃ (lead-free) are used as absorber materials, <span><math altimg=\"eq-00001.gif\" display=\"inline\" overflow=\"scroll\"><msub><mrow><mstyle><mtext mathvariant=\"normal\">Cu</mtext></mstyle></mrow><mrow><mn>2</mn></mrow></msub><mstyle><mtext mathvariant=\"normal\">O</mtext></mstyle></math></span><span></span> and NiO have been used as Hole Transport Layer (HTL) materials and TiO₂ as Electron Transport Layer (ETL) materials. ETL materials, in general, have more concern with stability issues and HTL materials have more issues with efficiency improvements. The effect of changing thickness, doping density and defect density of the absorber layer, as well as HTL, defect density of absorber/HTL interface and work functions of front and back contacts on the performance of the proposed devices, are investigated. To enhance the device performance, optimization of the device parameters is performed. After optimization of different parameters, it is observed that the lead-based device structure TiO₂/CH₃NH₃PbI₃/NiO has a maximum efficiency of 29.94%. Even the corresponding lead-free device structure TiO₂/CsGeI₃/NiO exhibits a maximum efficiency of 29.19%. Additionally, this study delved into the influence of altering series and shunt resistances, as well as temperature on the operational characteristics of the lead-free optimized device. Such eco-friendly and cost-effective alternatives as lead-free perovskite cells can be very promising for future work.</p>","PeriodicalId":14108,"journal":{"name":"International Journal of Modern Physics B","volume":"21 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140153160","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":"Luminescence of some lanthanides in synthetic yttrium gagarinite (NaCaYF6)","authors":"Shruti Dhale, Nilesh S. Ugemuge, Renuka Nafdey, Vartika S. Singh, Sanjiv V. Moharil","doi":"10.1142/s0217979225500377","DOIUrl":"https://doi.org/10.1142/s0217979225500377","url":null,"abstract":"<p>NaCaYF₆ is the formula for gagarinite. Noting the lack of luminescence studies in this material, we synthesized it using the hydrothermal method and investigated the luminescence of several lanthanides. Characteristic luminescence of Eu<span><math altimg=\"eq-00001.gif\" display=\"inline\" overflow=\"scroll\"><msup><mrow></mrow><mrow><mn>3</mn><mo>+</mo></mrow></msup></math></span><span></span>, Dy<span><math altimg=\"eq-00002.gif\" display=\"inline\" overflow=\"scroll\"><msup><mrow></mrow><mrow><mn>3</mn><mo>+</mo></mrow></msup></math></span><span></span>, Sm<span><math altimg=\"eq-00003.gif\" display=\"inline\" overflow=\"scroll\"><msup><mrow></mrow><mrow><mn>3</mn><mo>+</mo></mrow></msup></math></span><span></span> and Tb<span><math altimg=\"eq-00004.gif\" display=\"inline\" overflow=\"scroll\"><msup><mrow></mrow><mrow><mn>3</mn><mo>+</mo></mrow></msup></math></span><span></span> was observed. Detailed results on photoluminescence emission and excitation spectra, lifetime, chromaticity coordinates and concentration dependence of emission intensity are presented. Except for Tb<span><math altimg=\"eq-00005.gif\" display=\"inline\" overflow=\"scroll\"><msup><mrow></mrow><mrow><mn>3</mn><mo>+</mo></mrow></msup></math></span><span></span>, which exhibits f-d excitation, the luminescence of other activators got quenched at 1<span><math altimg=\"eq-00006.gif\" display=\"inline\" overflow=\"scroll\"><mspace width=\".17em\"></mspace></math></span><span></span>mol % concentration. Eu<span><math altimg=\"eq-00007.gif\" display=\"inline\" overflow=\"scroll\"><msup><mrow></mrow><mrow><mn>3</mn><mo>+</mo></mrow></msup></math></span><span></span> emission in this host was peculiar, in that the emissions from higher ⁵D states were observed. Luminescence characteristics are explained using the known energy level diagrams for the lanthanide activators.</p>","PeriodicalId":14108,"journal":{"name":"International Journal of Modern Physics B","volume":"142 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140153155","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":"Investigating the preferential sites of Co2+ substitution in SrCoxFe12−xO19 using Mössbauer spectroscopy","authors":"Hengjian Hou, Zheng Li, Zeyi Lu, Jiyu Shen, Zhongjin Wu, Jiangbo Yang, Kaiyang Gao, Yanfang Xia","doi":"10.1142/s0217979225500353","DOIUrl":"https://doi.org/10.1142/s0217979225500353","url":null,"abstract":"&lt;p&gt;In this paper, a series of M-type hexagonal SrCo&lt;sub&gt;&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt;Fe&lt;span&gt;&lt;math altimg=\"eq-00006.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;O&lt;span&gt;&lt;math altimg=\"eq-00007.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mn&gt;9&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt; (&lt;span&gt;&lt;math altimg=\"eq-00008.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;, 0.25, 0.5) samples have been prepared by sol–gel method. X-ray diffraction (XRD) showed that the samples produced were all p63/mmc space groups of single hexagonal crystals, and the lattice parameters &lt;i&gt;a&lt;/i&gt;, &lt;i&gt;b&lt;/i&gt; and &lt;i&gt;c&lt;/i&gt; did not show the expected trend with increasing &lt;i&gt;x&lt;/i&gt;. This was related to the valence changes and lattice distortion caused by the substitution of Co&lt;span&gt;&lt;math altimg=\"eq-00009.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt; at the 2a and 4f&lt;sub&gt;2&lt;/sub&gt; sites. Room temperature Mössbauer spectra studies showed that when &lt;span&gt;&lt;math altimg=\"eq-00010.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;, Fe&lt;span&gt;&lt;math altimg=\"eq-00011.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt; ions were not uniformly distributed, preferring the 4f&lt;sub&gt;1&lt;/sub&gt;, 4f&lt;sub&gt;2&lt;/sub&gt; and 2a sites; when &lt;span&gt;&lt;math altimg=\"eq-00012.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;, Co&lt;span&gt;&lt;math altimg=\"eq-00013.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt; ions preferentially displaced the 2a and 4f&lt;sub&gt;2&lt;/sub&gt; sites and the presence of Fe&lt;span&gt;&lt;math altimg=\"eq-00014.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt; was detected; when &lt;span&gt;&lt;math altimg=\"eq-00015.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;, Co&lt;span&gt;&lt;math altimg=\"eq-00016.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt; ions preferentially displaced the 4f&lt;sub&gt;1&lt;/sub&gt; and 2b sites and the percentage of Fe&lt;span&gt;&lt;math altimg=\"eq-00017.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt; occupancy was reduced, with a greater occupancy (&lt;span&gt;&lt;math altimg=\"eq-00018.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;R&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;A&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo stretchy=\"false\"&gt;)&lt;/mo&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt; occurring at the 12k site, indicating a preference of Fe&lt;span&gt;&lt;math altimg=\"eq-00019.g","PeriodicalId":14108,"journal":{"name":"International Journal of Modern Physics B","volume":"50 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140153161","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":"Synthesis, characterization and properties of Cr-doped ZnO nanoparticles via a facile solvothermal route","authors":"L. Renuga Devi, E. Selva Esakki, S. Meenakshi Sundar","doi":"10.1142/s0217979225500158","DOIUrl":"https://doi.org/10.1142/s0217979225500158","url":null,"abstract":"<p>Cr-doped ZnO (<span><math altimg=\"eq-00001.gif\" display=\"inline\" overflow=\"scroll\"><mi>x</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>0</mn><mn>2</mn></math></span><span></span>–0.08) nanoparticles are synthesized using the microwave solvothermal irradiation technique. The final product is calcinated at 450^∘C and the nanostructure of the material is investigated using various techniques. In structural studies, XRD analysis shows that the hexagonal wurtzite structure of ZnO is present in the standard JCPDS card. FESEM spectrum reveals the hexagonal shape of the synthesized samples and EDS provides information on the qualitative composition of the nanoparticles. Optical absorbance images show exciton peaks in the UV region, which can be attributed to Cr incorporation into the ZnO lattice, and the optical energy bandgap values are calculated using the tauc plot method. Photoluminescence (PL) emission spectra are measured using PL spectroscopy. Interestingly, vibrating sample magnetometry (VSM) reveals enhancements in the magnetic properties in M–H loops and it is widely used for biological applications like antibacterial activity.</p>","PeriodicalId":14108,"journal":{"name":"International Journal of Modern Physics B","volume":"50 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140152999","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":"Effect of tensile and compressive strains on the electronic structure of O-atom-doped monolayer MoS2","authors":"Wang Jia-Xin, Liu Gui-Li, Wei Lin, Jiao Gan, Zhang Guo-Ying","doi":"10.1142/s0217979225500122","DOIUrl":"https://doi.org/10.1142/s0217979225500122","url":null,"abstract":"<p>We investigate the effects of biaxial tensile and compressive strains on the electronic structure of O-doped monolayer MoS₂ by density functional theory (DFT) in this paper. O-doped monolayer MoS₂ is an exothermic reaction. The doping of O leads to the transformation of the system from direct bandgap to indirect, and the bonding of Mo and O causes a large amount of charge transfer. The application of tensile strain leads to a decrease in the stability of the doped system, and the system always maintains the nature of indirect bandgap. The degree of interatomic charge transfer and bandgap value gradually decrease with the increase of tensile strain. The application of compression strain improves the stability of the doped system, and as the compressive strain increases, the bandgap of the doped system completes the indirect–direct–indirect transformation. The bandgap value shows a trend of increasing and then decreasing. Additionally, the degree of charge transfer between atoms is strengthened.</p>","PeriodicalId":14108,"journal":{"name":"International Journal of Modern Physics B","volume":"20 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140152995","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":"Models based analysis of radiative induced MHD hybrid nanofluid flow over an exponentially stretching sheet","authors":"Nasrullah Khan, Nadeem Abbas, Aqila Shaheen, Wasfi Shatanawi","doi":"10.1142/s021797922550033x","DOIUrl":"https://doi.org/10.1142/s021797922550033x","url":null,"abstract":"<p>The study focuses on the flow of hybrid nanofluid, induced by magnetic and radiation effects, across an exponentially stretched sheet. The research examines the impact of temperature-dependent properties of the hybrid nanofluid on the sheet. Water is used as the base fluid, and SWCNT and MWCNT are employed as nanoparticles. The study includes a discussion of the Yamada–Ota, Xue and Tiwari–Das models of hybrid nanofluids. The governing system of flow is presented mathematically, and boundary layer approximations are used to reduce differential equations. The differential equations are transformed into dimensionless ordinary differential equations (ODEs) by using transformations. The dimensionless system of equations is then solved numerically. The results of the flow model are offered in tabular and graphical forms. We observed that Tiwari–Das model of hybrid nanofluid achieved more heat transfer and friction factor values when compared to other models of Xue and Yamada–Ota models of hybrid nanofluid. Temperature curves are noted to be enhanced by enlargement in the nano-concentration factor. If the nano-concentration increased in the fluid which boosted the thermal conductivity of the liquid, then as a result, the temperature of fluid enhanced at surface.</p>","PeriodicalId":14108,"journal":{"name":"International Journal of Modern Physics B","volume":"98 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140153162","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":"Landau–Zener–Stückelberg–Majorana-like dynamics induced by tunneling of spin qubit states in a multiband two-state magnetic quantum wire","authors":"S. E. Mkam Tchouobiap, L. C. Fai","doi":"10.1142/s0217979225500134","DOIUrl":"https://doi.org/10.1142/s0217979225500134","url":null,"abstract":"<p>We investigate the transfer between spin quantum bit (qubit) states and study the Landau–Zener–Stückelberg–Majorana (LZSM)-like dynamics of tunneling spin qubits in a multiband two-state magnetic quantum wire. Indeed, within the framework of an optical parabolic potential in a three-dimensional (3D) heterostructure quantum wire and under the influence of an external time-varying magnetic field, a model for a multiband two-state magnetic quantum wire is developed. Here, the external magnetic field is used to coherently manipulate and control spin qubit states. By driving the system through an avoided crossing, we consider the associated effective quantum two-level system (TLS) related to the spin qubit states in each band, driving by an external coherent magnetic field in which the related Hamiltonian is Hermitian, and which generally paves a way to LZSM interferometry. Thus, we establish the analytical expressions of the energy eigenvalues in each band and derive the analytical solution of the dynamical evolution of the tunneling probabilities of the associated TLS. Accordingly, nonadiabatic and adiabatic tunneling probabilities (survival and transition) are calculated for each band of the multiband TLS. In this respect, the nonadiabatic and adiabatic dynamical evolutions of the tunneling probabilities of spin qubit populations in the first four bands, with band quantum numbers <i>n</i> = 0, 1, 2 and 3 are analyzed. As a result, depending on the amplitude strength of the driven magnetic field and the magnitude of the driving frequency, we report two striking nonadiabatic and adiabatic scenarios in each band for both the diabatic and adiabatic states. In this context, driving the two states of each band of the multiband TLS related to the spin qubit states through an avoided level crossing can result in nontrivial and incoherent dynamics at certain phases, resulting to apparent inaccurate probabilities, especially in the case of strong driven magnetic field and high driving frequency.</p>","PeriodicalId":14108,"journal":{"name":"International Journal of Modern Physics B","volume":"120 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140152997","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 electro-optical properties of germanene nanoribbons by boron atom substitution for application in information transmission","authors":"Hoang Van Ngoc, Chu Viet Ha","doi":"10.1142/s021797922550016x","DOIUrl":"https://doi.org/10.1142/s021797922550016x","url":null,"abstract":"<p>Germanene nanoribbons, a one-dimensional material, have great potential for future technological applications. This research aims to investigate the electro-optical properties of boron-doped germanene nanoribbons with a width of five atoms. The theory used in this study is density functional theory (DFT). The original system is a narrow band gap semiconductor, with a gap size of 0.06<span><math altimg=\"eq-00001.gif\" display=\"inline\" overflow=\"scroll\"><mspace width=\".17em\"></mspace></math></span><span></span>eV. The doped configurations, which retain the honeycomb hexagonal structure, are stable and metallic in nature. The introduction of B atoms flattens the configuration, leading to a partial charge shift from Ge to B. The absorption peaks in the 3B and 5B configurations occur in the frequency range less than 500<span><math altimg=\"eq-00002.gif\" display=\"inline\" overflow=\"scroll\"><mspace width=\".17em\"></mspace></math></span><span></span>nm, indicating good absorption of visible light, and suggesting possible applications in light-sensitive components. Notably, the real part of the dielectric function’s 0z component is negative, offering immense potential for optical, microwave and communication applications.</p>","PeriodicalId":14108,"journal":{"name":"International Journal of Modern Physics B","volume":"10 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140152926","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}