Journal of Superconductivity and Novel Magnetism最新文献

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Charge Transport Properties in Two-dimensional Topologically Trivial and Nontrivial Mexican Hat-like Systems 二维拓扑平凡与非平凡Mexican Hat-like系统的电荷输运性质
IF 1.7 4区 物理与天体物理
Journal of Superconductivity and Novel Magnetism Pub Date : 2026-03-17 DOI: 10.1007/s10948-026-07152-5
Karla Lemac, Zoran Rukelj
{"title":"Charge Transport Properties in Two-dimensional Topologically Trivial and Nontrivial Mexican Hat-like Systems","authors":"Karla Lemac,&nbsp;Zoran Rukelj","doi":"10.1007/s10948-026-07152-5","DOIUrl":"10.1007/s10948-026-07152-5","url":null,"abstract":"<div>\u0000 \u0000 <p>In this paper we study and compare the single-particle and selected electronic transport properties of a topologically trivial (TT) and topologically nontrivial (TNT) two-dimensional system with two Mexican-hat-like valence bands. Both TT and TNT cases are described by 2<span>(times)</span>2 effective Hamiltonian matrices from which the density of state, the total and effective charge carrier concentration, the Hall coefficient, and the real part of the interband conductivity are calculated. The main result is that electron-doped TT and TNT cases cannot be distinguished on the basis of the intraband transport quantities like the Drude spectral weight or the zero-field Hall coefficient. Moreover it is shown that intraband properties depend only on the energy of the band minimum and the local maximum. The two topological cases can be differentiated in the interband charge transport, like in the real part of the interband conductivity, which is given in terms of the band minimum and local maximum transition energies with two experimentally observable differences between TT and TNT cases.</p>\u0000 </div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"39 2","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147560086","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
Structural, Optical, Magnetic and Dielectric Properties of Europium Substituted Zinc Ferrite Nanostructures Synthesized By Coprecipitation Method 共沉淀法合成铕取代铁氧体锌纳米结构的结构、光学、磁性和介电性能
IF 1.7 4区 物理与天体物理
Journal of Superconductivity and Novel Magnetism Pub Date : 2026-03-16 DOI: 10.1007/s10948-026-07139-2
B. Uday Kumar, T. Ramesh, K. Kiran Kumar, K. Vani, S. Katlakunta, K. Praveena
{"title":"Structural, Optical, Magnetic and Dielectric Properties of Europium Substituted Zinc Ferrite Nanostructures Synthesized By Coprecipitation Method","authors":"B. Uday Kumar,&nbsp;T. Ramesh,&nbsp;K. Kiran Kumar,&nbsp;K. Vani,&nbsp;S. Katlakunta,&nbsp;K. Praveena","doi":"10.1007/s10948-026-07139-2","DOIUrl":"10.1007/s10948-026-07139-2","url":null,"abstract":"<div>\u0000 \u0000 <p>Europium-substituted zinc ferrite nanoparticles (ZnFe<sub>2-x</sub>Eu<sub>x</sub>O<sub>4</sub> (0 ≤ x ≤ 0.1)) were synthesized using the coprecipitation method, and then samples were prepared using conventional sintering at 950 °C for 3 h. The structural properties of the synthesized samples were studied using X-ray diffraction (XRD). The Williamson–Hall (W-H) method is used to measure the crystallite size and lattice strain values of the samples. Considerable changes in the lattice parameter, X-ray density, and crystallite size are observed with Eu substitution. The morphology and grain size of the samples were investigated using field-emission scanning electron microscopy (FE-SEM) images. Grains are not uniform, and a reduction in grain size from 178 nm to 84 nm upon Eu doping. Fourier-transform infrared spectroscopy (FTIR) confirmed the presence of metal–oxygen vibrations corresponding to the absorption bands of both the tetrahedral and octahedral sites of the spinel ferrite structure. Optical properties showed a gradual increase in the optical band gap with higher Eu substitution. Magnetic hysteresis (VSM) loops exhibited unsaturated magnetization in the measured magnetic field (± 15 kOe) range. A decrease in saturation magnetization is observed with increasing Eu content, and the coercivity values range from 36 Oe to 64 Oe. A reduction in dielectric constant and dielectric loss was also observed with Eu incorporation. The modifications in the structural, optical, magnetic, and dielectric properties were interpreted based on appropriate theoretical considerations. Overall, Europium-doped zinc ferrites exhibit promising multifunctional capabilities for advanced technological applications.</p>\u0000 </div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"39 2","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147559880","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
Structural, Optical, and Magnetic Properties of Eu3+-Substituted Ni-Mg Ferrites Synthesized via Hydrothermal Method 水热法合成Eu3+取代Ni-Mg铁氧体的结构、光学和磁性能
IF 1.7 4区 物理与天体物理
Journal of Superconductivity and Novel Magnetism Pub Date : 2026-03-16 DOI: 10.1007/s10948-026-07154-3
Vanthini N. Adoons, Lebogang Kotsedi, Delicacy Ntshalintshali, Thandeka Molefe, Ahmed U. Yimamu, Teboho P. Mokoena
{"title":"Structural, Optical, and Magnetic Properties of Eu3+-Substituted Ni-Mg Ferrites Synthesized via Hydrothermal Method","authors":"Vanthini N. Adoons,&nbsp;Lebogang Kotsedi,&nbsp;Delicacy Ntshalintshali,&nbsp;Thandeka Molefe,&nbsp;Ahmed U. Yimamu,&nbsp;Teboho P. Mokoena","doi":"10.1007/s10948-026-07154-3","DOIUrl":"10.1007/s10948-026-07154-3","url":null,"abstract":"<div>\u0000 \u0000 <p>Eu<sup>3+</sup> substituted nickel-magnesium ferrites with the formula Ni<sub>0.5</sub>Mg<sub>0.5</sub>Eu<sub><i>x</i></sub>Fe<sub>2−<i>x</i></sub>O<sub>4</sub> (<i>x</i> = 0.0-0.12) were successful synthesized by hydrothermal method. Herein, we investigate the effect of varying Eu<sup>3+</sup> substitution levels on the structural, optical, and magnetic properties of the resulting ferrites. X-ray diffraction (XRD) analysis confirmed the formation of a cubic spinel structure as the dominant phase, however, at higher Eu<sup>3+</sup> concentrations, additional diffraction peaks corresponding to a secondary hematite phase were observed, indicating a solubility limit of Eu<sup>3+</sup> in the spinel lattice. A progressive increase in crystallite size and lattice parameter was observed with increasing Eu<sup>3+</sup> content. Transmission electron microscopy (TEM) analysis revealed the formation of nearly spherical nanoparticles with sizes ranging 46–63 nm. Fourier-transform infrared (FTIR) spectroscopy confirmed the presence of metal-oxygen bonds in the samples through their characteristic vibrations, while diffuse reflectance spectroscopy (DRS) revealed an increase in band gap energy from 1.82 eV to 2.12 eV, suggesting structural and electronic modifications at higher Eu<sup>3+</sup> substitution levels. All samples showed ferromagnetic behaviour, as measured by vibrating sample magnetometry (VSM); however, saturation magnetization, coercivity, and remanence decreased with increasing Eu<sup>3+</sup> content. These results highlight the potential of Eu-substituted Ni-Mg ferrites for applications in magneto-optical devices, high-frequency electronics, and spintronic technologies.</p>\u0000 </div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"39 2","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10948-026-07154-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147559881","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}
引用次数: 0
Defect-Induced Softening of Magnetic Interactions in Sb and Sm Doped Co3O4±δ 掺杂Co3O4±δ的Sb和Sm中磁相互作用的缺陷诱导软化
IF 1.7 4区 物理与天体物理
Journal of Superconductivity and Novel Magnetism Pub Date : 2026-03-10 DOI: 10.1007/s10948-026-07156-1
Jisna Rahman, Gowtham V, Rajeevan NE, Ranjith Ramadurai, Asokan Kandasami
{"title":"Defect-Induced Softening of Magnetic Interactions in Sb and Sm Doped Co3O4±δ","authors":"Jisna Rahman,&nbsp;Gowtham V,&nbsp;Rajeevan NE,&nbsp;Ranjith Ramadurai,&nbsp;Asokan Kandasami","doi":"10.1007/s10948-026-07156-1","DOIUrl":"10.1007/s10948-026-07156-1","url":null,"abstract":"<div>\u0000 \u0000 <p>Cobalt oxide (Co₃O₄) is a rare-earth-free spinel material with ferromagnetic ordering, making it a promising candidate for microwave and spintronics applications. This study investigates the controlled introduction of lattice defects through antimony (Sb) and samarium (Sm) doping in Co₃O₄ to tune its magnetic properties. Substitution of Sm and Sb is expected to generate oxygen vacancies (V<sub>o</sub>) and modify cation distribution, thereby altering magnetic ordering. Structural refinement confirms that undoped Co₃O₄ crystallizes in a cubic spinel structure with space group F<span>(stackrel{prime }{4})</span>3m. Doping with Sb and Sm ions leads to traces of SbO<sub>2</sub>. X-ray photoelectron spectroscopy (XPS) reveals that dopant incorporation disrupts the super-exchange pathways that govern spin orientation. This disruption weakens ferromagnetic interactions, as reflected in the softening of magnetic hysteresis and reduction of coercive fields in the doped samples. While pristine Co₃O₄ exhibits signatures of canted magnetic ordering at room temperature, doping modifies super-exchange strengths and bond angles, leading to further magnetic softening. Additionally, the dopants induce a structural transition from a normal spinel to a mixed-spinel character, as supported by XPS analysis. Overall, Sm and Sb doping provide an effective route to defect engineering in Co₃O₄, enabling controlled modulation of magnetic interactions for functional device applications.</p>\u0000 </div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"39 2","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147441219","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
Computational Investigations of Mo2XT2 (X = C, N; T = F, O) MXenes for Optoelectronic Applications 光电应用中Mo2XT2 (X = C, N; T = F, O) MXenes的计算研究
IF 1.7 4区 物理与天体物理
Journal of Superconductivity and Novel Magnetism Pub Date : 2026-03-08 DOI: 10.1007/s10948-026-07174-z
Bakhtiar Ul Haq, Se-Hun Kim, R. Ahmed, Aijaz Rasool Chaudhry, Adnan Ali, Mohammed Benali Kanoun, Souraya Goumri-Said, Zulfiqar Ali Shah
{"title":"Computational Investigations of Mo2XT2 (X = C, N; T = F, O) MXenes for Optoelectronic Applications","authors":"Bakhtiar Ul Haq,&nbsp;Se-Hun Kim,&nbsp;R. Ahmed,&nbsp;Aijaz Rasool Chaudhry,&nbsp;Adnan Ali,&nbsp;Mohammed Benali Kanoun,&nbsp;Souraya Goumri-Said,&nbsp;Zulfiqar Ali Shah","doi":"10.1007/s10948-026-07174-z","DOIUrl":"10.1007/s10948-026-07174-z","url":null,"abstract":"<div>\u0000 \u0000 <p>MXenes are regarded as highly promising two-dimensional (2D) materials for next-generation device applications and are therefore extensively explored in recent years. Here, we explore MXenes based on Mo<sub>2</sub>XT<sub>2</sub> (X = C, N; T = F, O) derived from Mo<sub>2</sub>SiC MAX phase for applications in modern technologies. Through the computational approach, the physical properties of Mo<sub>2</sub>XT<sub>2</sub> MXenes were explored, considering variations in X-elements and functional groups. The studied MXenes exhibited metal-like behavior where the Mo-<i>d</i> states appear over the Fermi level, a feature inherited from the MAX phases. Moreover, the electronic structures of the studied MXenes demonstrated nearly similar band arrangements for the up and down spin channels when functionalized with oxygen. In contrast, the MXenes functionalized with fluorine showed relatively asymmetrical electronic structures. The different spin-up and down electronic states have induced magnetic moments of magnitude 2.10 μ<sub>β</sub> for Mo<sub>2</sub>CF<sub>2</sub>, 3.13 μ<sub>β</sub> for Mo<sub>2</sub>NF<sub>2</sub>, 0.75 μ<sub>β</sub> for Mo<sub>2</sub>CO<sub>2</sub>, and 1.41 μ<sub>β</sub> for Mo<sub>2</sub>NO<sub>2</sub>. The refractive index values for the Mo<sub>2</sub>XT<sub>2</sub> MXenes remain larger than 1 for electromagnetic light with energy levels below 6 eV. These 2D materials demonstrated interesting optical properties that might be useful in optoelectronic devices.</p>\u0000 </div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"39 2","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147737610","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 Study of the Environmental Impact on Gap Relaxation Time in NbTi Superconducting Wire 环境对NbTi超导线隙弛豫时间影响的动态研究
IF 1.7 4区 物理与天体物理
Journal of Superconductivity and Novel Magnetism Pub Date : 2026-03-05 DOI: 10.1007/s10948-026-07147-2
K. Harrabi
{"title":"Dynamic Study of the Environmental Impact on Gap Relaxation Time in NbTi Superconducting Wire","authors":"K. Harrabi","doi":"10.1007/s10948-026-07147-2","DOIUrl":"10.1007/s10948-026-07147-2","url":null,"abstract":"<div>\u0000 \u0000 <p>We have studied non-equilibrium states in NbTi films deposited on fused silica under different surrounding conditions using electrical current pulses. When the applied current exceeds the depairing current <span>(I_{c})</span>, a voltage response is observed after a characteristic delay time <span>(t_{d})</span>. Although the sample dimensions are much larger than the coherence length <span>(xi)</span>, the localized micro-metric region formed corresponds to a hotspot. The delay times are quantitatively described using the Time-Dependent Ginzburg–Landau (TDGL) theory of M. Tinkham, enabling the determination of filament cooling times for the same sample in both liquid helium and vacuum. We find cooling times of about <span>(tau _{d} = 6.0 pm 0.5)</span> ns in vacuum and <span>(5.3 pm 0.5)</span> ns in liquid helium. These results demonstrate that liquid helium has only a minor effect on the film cooling time, with most of the heat being transferred into the substrate via phonons. </p>\u0000 </div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"39 2","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147363222","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
Crystal Symmetry Effects on Oxygen Doping Distribution, SC, and Phase Diagram in YBa2Cu3O7 晶体对称对YBa2Cu3O7中氧掺杂分布、SC和相图的影响
IF 1.7 4区 物理与天体物理
Journal of Superconductivity and Novel Magnetism Pub Date : 2026-03-03 DOI: 10.1007/s10948-026-07136-5
Bassam M. Mustafa
{"title":"Crystal Symmetry Effects on Oxygen Doping Distribution, SC, and Phase Diagram in YBa2Cu3O7","authors":"Bassam M. Mustafa","doi":"10.1007/s10948-026-07136-5","DOIUrl":"10.1007/s10948-026-07136-5","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 &lt;p&gt;The discovery of high-temperature superconductivity (HTSC) in La&lt;sub&gt;2 − x&lt;/sub&gt;Sr&lt;sub&gt;x&lt;/sub&gt;CuO&lt;sub&gt;4&lt;/sub&gt; by Müller [1] in 1986 marked a new era in the history of science. Soon, Wu et al. [2]. in 1987 discovered YBa&lt;sub&gt;2&lt;/sub&gt;Cu&lt;sub&gt;3&lt;/sub&gt;O&lt;sub&gt;7&lt;/sub&gt; (YBCO), which led to great achievements in all advanced fields of science and technology. However, still no consensus on a theoretical model to describe superconductivity (SC), the phase diagram (PD), and abnormalities in YBCO and other high-Tc cuprates, including the HTSC mechanism itself. In my former paper [3] studied SC in La&lt;sub&gt;2 − x&lt;/sub&gt;Sr&lt;sub&gt;x&lt;/sub&gt;CuO&lt;sub&gt;4&lt;/sub&gt; (LBCO) using crystal symmetry effects on the distribution of Sr2 + atoms in the parent crystal, using the principles: (1) Crystal symmetry affects the distribution of Sr2 + dopants on lattice sites of the parent compound; (2) Sr2 + dopants affect lattice symmetry and SC. This gives a new vision for SC in LBCO and may be for other cuprates. For LBCO: 1-By a statistical method discovered that distances between doped LBCO crystals by O atoms equals coherence the length (CL) at the concentration of start of SC; 2- Using a model for the PD depending on distribution of (1 &amp; 2 ) Sr2 + dopants ( leads to max Tc, adding more atoms decline it )for all the lattice sites each leads to represent a new phase in PD, thus succeed in explanations of the unclear changes in the phase diagram were obtained. Here in this research, the method is extended to study HTSC of YBa&lt;sub&gt;2&lt;/sub&gt;Cu&lt;sub&gt;3&lt;/sub&gt;O&lt;sub&gt;7&lt;/sub&gt;.The compound YBCO is different in crystal structure and doping mechanism from LSCO, but the active element in both is the CuO layer, however the method with modifications leads to fruitful results includes:1- Determination of the correct theoretical value of the coherence length (CL) for YBCO by applying symmetry effects to find relation between the distance between doped YBCO crystals and corresponding hole concentration, for this task, two methods were designed i.e. statistical and the matrix methods, it was found ( by statistical method for YBCO, CL = 16.8 Å; by matrix method CL = 16.33 Å) these are in excellent agreement with experimental values when the hole concentration is ( 0.05), at which SC started; 2- Phase coherence will not started unless the distances between dopants is within the CL. So one of the lost fundamentals puzzles in HTSC in cuprates may be found, (may be the lost fundamental point that researchers seek )because CL is a basic concept in HTSC, linked with phase coherence which is the third and the control operation needed to start SC after charge parring and condensation ;3- This leads to understand that SC occurs in three stages: parring of charge carriers during hole doping instant, and condensation of charged pairs to low energy levels, and Phase coherence which occurs due to interaction between YBCO crystals doped with holes. 4- This leads to considering that the two ","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"39 2","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147336726","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
Alternative Methods for the Transformation of kπ-skyrmions in Uniaxial Nanoscale Modified Films 单轴纳米改性薄膜中kπ-skyrmions转化的几种方法
IF 1.7 4区 物理与天体物理
Journal of Superconductivity and Novel Magnetism Pub Date : 2026-03-02 DOI: 10.1007/s10948-026-07153-4
R. M. Vakhitov, G. F. Ilyasova, M. A. Filippov
{"title":"Alternative Methods for the Transformation of kπ-skyrmions in Uniaxial Nanoscale Modified Films","authors":"R. M. Vakhitov,&nbsp;G. F. Ilyasova,&nbsp;M. A. Filippov","doi":"10.1007/s10948-026-07153-4","DOIUrl":"10.1007/s10948-026-07153-4","url":null,"abstract":"<div>\u0000 \u0000 <p>The paper considers micromagnetic structures arising in a uniaxial disk-shaped ferromagnet containing columnar “potential well” type defect located at its center, within which the material parameters are altered. It was shown that in the disk (in the absence of a defect), <span>(:kpi:)</span>-skyrmions (<span>(:k=1,:2,dots:7)</span>) are alternately stabilized depending on the defect radius. It was found that in this case, the transformation of the disk’s micromagnetic structure from a state with <span>(:kpi:)</span>-skyrmions occurs through the widening of its rings and the formation of a transition region at the disk edge, in which the magnetization vector once again rotates by 180°. Taking into account the presence of the defect, skyrmion stabilization occurs according to a different scenario: the transformation of <span>(:kpi:)</span>-skyrmions into <span>(:(k+1)pi:)</span>-skyrmions in the central region of the disk, corresponding to the core. In addition, it was found that the critical disk dimensions at which these transformations occur are significantly lower than in the absence of a defect in the disk, which potentially simplifies the production of more complex skyrmions in structure.</p>\u0000 </div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"39 2","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147336314","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
Dependence of the Band Gap in CuO monolayer on Coulomb Interactions and Magnitude of the Hopping Integrals CuO单层带隙与库仑相互作用及跳变积分大小的关系
IF 1.7 4区 物理与天体物理
Journal of Superconductivity and Novel Magnetism Pub Date : 2026-02-28 DOI: 10.1007/s10948-026-07148-1
Ilya Makarov, Igor Nekrasov, Maxim Korshunov
{"title":"Dependence of the Band Gap in CuO monolayer on Coulomb Interactions and Magnitude of the Hopping Integrals","authors":"Ilya Makarov,&nbsp;Igor Nekrasov,&nbsp;Maxim Korshunov","doi":"10.1007/s10948-026-07148-1","DOIUrl":"10.1007/s10948-026-07148-1","url":null,"abstract":"<div>\u0000 \u0000 <p>The band structure, orbital contributions to the spectral weight of the states at the top of the valence band, and the type of band gap in a CuO monolayer are investigated for different values of the hopping integrals and the Coulomb interactions on copper, <span>(U'_d)</span>, and oxygen, <span>(U'_p)</span>. The electronic structure of quasiparticle excitations is calculated using an eight-band <i>p</i>–<i>d</i> model that includes all Cu 3<i>d</i> and O 2<i>p</i> orbitals, together with the generalized tight-binding method and the the equations of motion method for Green’s functions of Hubbard operators within the multiband Hubbard model. The energy spectrum of local states and dispersionless quasiparticle excitations is obtained. The ratio <span>({{U'_d}}/ {{U'_p}})</span> determines both the magnitude and the type of the band gap. Depending on this ratio, Mott–Hubbard (MH), charge-transfer (CT), or interorbital band gap can arise. When <span>(U'_d)</span> dominates over <span>(U'_p)</span>, the system is insulating, with a band gap opening between <i>d</i>-orbitals. A metallic state can be realized only when <span>(U'_p)</span> exceeds <span>(U'_d)</span>. The metal–insulator transition driven by increasing hopping integrals is possible only for <span>(U'_d &lt; 1.5U'_p)</span>.</p>\u0000 </div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"39 2","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147342791","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
First-Principles Investigation of Superconductivity in Dy-Intercalated Bilayer Graphene Under High Pressure 高压下镝嵌层双层石墨烯超导性的第一性原理研究
IF 1.7 4区 物理与天体物理
Journal of Superconductivity and Novel Magnetism Pub Date : 2026-02-25 DOI: 10.1007/s10948-026-07151-6
Yandong Yang
{"title":"First-Principles Investigation of Superconductivity in Dy-Intercalated Bilayer Graphene Under High Pressure","authors":"Yandong Yang","doi":"10.1007/s10948-026-07151-6","DOIUrl":"10.1007/s10948-026-07151-6","url":null,"abstract":"<div>\u0000 \u0000 <p>This study investigates the superconducting properties of Dy-intercalated bilayer graphene (<span>(DyC_6)</span>) using first-principles calculations. Under an applied pressure of 2 GPa, the electronic structure and electron-phonon coupling of <span>(DyC_6)</span> are evaluated within the EPW module of Quantum ESPRESSO. The results reveal a metallic multi-band Fermi surface with several bands crossing the Fermi level, indicative of strong electron-phonon coupling. The calculated electron-phonon coupling constant is <span>(lambda )</span>= 0.929, and the superconducting critical temperature is predicted to be <span>(Tc approx )</span> 11.14 K, with a superconducting gap of 1.69 meV. Analysis of the Eliashberg spectral function shows that superconductivity arises from the synergistic contribution of low-frequency Dy-related phonon modes and high-frequency C-related modes. Despite the inherent magnetic moment of Dy, calculations indicate that its magnetism is nearly quenched in the <span>(DyC_6)</span> system due to hybridization with carbon layers, allowing BCS-type phonon-mediated superconductivity to emerge. This work predicts <span>(DyC_6)</span> as a promising graphene-based superconductor and provides a theoretical basis for integrating magnetic rare-earth elements into two-dimensional materials to engineer superconducting properties.</p>\u0000 </div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"39 2","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147341490","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}
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