Physica C-superconductivity and Its Applications最新文献

{"title":"Interfacial superconductivity in Cu/Cu2O and its effect on shielding ambient electric fields","authors":"Dale R. Harshman ,&nbsp;Anthony T. Fiory","doi":"10.1016/j.physc.2024.1354600","DOIUrl":"10.1016/j.physc.2024.1354600","url":null,"abstract":"<div><div>A model is presented for two-dimensional superconductivity at semiconductor-on-metal interfaces mediated by Coulomb interactions between electronically-active interface charges in the semiconductor and screening charges in the metal. The junction considered is native Cu₂O on Cu in which an interfacial double charge layer of areal density <em>n</em>, comprising superconducting holes in Cu₂O and mediating electrons in Cu, is induced in proportion to a sub-monolayer of adsorbed ⁴He atoms. Evidence for superconductivity on copper with prior air exposure is revealed in new analysis of previously published work function data. Based on a theory developed for layered superconductors, the intrinsic transition temperature <em>T</em>_C = β <em>n</em>^1/2/ζ is determined by <em>n</em> and transverse distance ζ ≃ 2.0 Å between the charge layers; β = 1.933(6) <em>e</em>²ƛ_C/<em>k</em>_B = 1247.4(3.7) K-Ų is a universal constant involving the reduced Compton wavelength of the electron ƛ_C. This model is applied to understanding the shielding of copper work-function patch and gravitational compression electric fields reported in the Witteborn-Fairbank gravitational electron free fall experiment. Interfacial superconductivity with <em>n</em> ≃ 1.6 × 10¹² cm⁻², <em>T</em>_C ≃ 7.9 K and Berezinskiĭ-Kosterlitz-Thouless temperature <em>T</em>_BKT ≃ 4.4 K accounts for the shielding observed at temperature <em>T</em> ≃ 4.2 K. Helium desorption and concomitant decreases in <em>n</em> and <em>T</em>_C replicate the temperature transition in ambient electric fields on falling electrons, as observed by Lockhart et al., and the vanishing of superconductivity above <em>T</em> ≃ 4.8 K.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"632 ","pages":"Article 1354600"},"PeriodicalIF":1.3,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143600738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Enhanced stability and optimization of SMES-based deregulated power systems using the repulsive firefly algorithm","authors":"Asit Mohanty ,&nbsp;Sthitapragyan Mohanty ,&nbsp;Pragyan P Mohanty ,&nbsp;Manzoore Elahi M. Soudagar ,&nbsp;S. Ramesh ,&nbsp;Javed Khan Bhutto ,&nbsp;Abdulwasa Bakr Barnawi ,&nbsp;Erdem Cuce","doi":"10.1016/j.physc.2025.1354692","DOIUrl":"10.1016/j.physc.2025.1354692","url":null,"abstract":"<div><div>The growing incorporation of renewable energy into deregulated power systems requires advanced hardware solutions, such as Superconducting Magnetic Energy Storage (SMES), as well as more complex control algorithms that surpass traditional Automatic Governor Control (AGC) methods based on PID or IPC techniques.</div><div>This paper introduces an innovative method utilizing the Repulsive Firefly Algorithm (RFA) for the dynamic management and optimization of a two-agent deregulated power system. The RFA, augmented with a repulsion mechanism, markedly enhances exploratory capabilities and reduces premature convergence, hence providing strong performance in extremely dynamic and uncertain grid settings. The proposed RFA-based method efficiently mitigates frequency fluctuations and optimizes power distribution across independent market entities by dynamically adjusting the control settings of the SMES and other system components. The fast response and exceptional efficiency of SMES are vital for stabilizing the power grid during fluctuations caused by renewable energy sources. Simulation results indicate that RFA surpasses traditional methods, providing enhanced control accuracy, diminished frequency fluctuations, and increased power flow stability. This study highlights the capability of RFA as a sophisticated optimization instrument for improving the resilience and efficiency of contemporary deregulated power systems that incorporate renewable energy sources.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"632 ","pages":"Article 1354692"},"PeriodicalIF":1.3,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143791772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Bending characteristics of multi-layer spiral HTS cable with large tape gap","authors":"Haosheng Ye,&nbsp;Xuan Zhou,&nbsp;Jie Sheng,&nbsp;Jinshan Yang,&nbsp;Zhijian Jin,&nbsp;Yue Zhao","doi":"10.1016/j.physc.2025.1354691","DOIUrl":"10.1016/j.physc.2025.1354691","url":null,"abstract":"<div><div>Assembling high-temperature superconducting (HTS) tapes into robust cable with spiral geometry is widely adopted to achieve high current-carrying capacity and strong mechanical properties in high-field magnet applications. However, multi-layer structure of spiral HTS cable undermines its bending performance due to complex factors, which have not been comprehensively clarified yet. In this paper, the influence of the tape gap on the bending characteristics of double-layer spiral HTS cable has been investigated through both experimental and numerical methods. and we revealed a distinct mechanism of critical current degradation during bending correlated with large tape gap. Result shows that, the large tape gap, as an unneglectable geometrical irregularity, leads to the increment of the interlayer friction coefficient. Moreover, with the increase of tape gap, additional compressive strain would be imposed on tape, leading to the exacerbation of imbalance of strain distribution. Therefore, cable samples with larger tape gap exhibit inferior bending performance compared to those with smaller tape gap, and this earlier occurrence of critical current degradation during bending process is primarily manifested in the outer layer. Conclusion obtained from this paper is anticipated to assist the understanding of the mechanism of bending performance degradation, as well as the improvement of engineering production for multi-layer spiral HTS cable.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"632 ","pages":"Article 1354691"},"PeriodicalIF":1.3,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143791771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"First-principles analysis of superconducting magnesium diboride under pressure using the Cooper pair distribution function Dcp(ω,Tc)","authors":"J.A. Camargo-Martínez ,&nbsp;G.I. González-Pedreros ,&nbsp;C. Vázquez-López","doi":"10.1016/j.physc.2025.1354677","DOIUrl":"10.1016/j.physc.2025.1354677","url":null,"abstract":"<div><div>The Cooper pair distribution function <span><math><mrow><msub><mrow><mi>D</mi></mrow><mrow><mi>c</mi><mi>p</mi></mrow></msub><mrow><mo>(</mo><mi>ω</mi><mo>,</mo><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span> is employed to analyze the behavior of the MgB<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> superconductor under pressures ranging from 8 to 32 GPa. The results of <span><math><mrow><msub><mrow><mi>D</mi></mrow><mrow><mi>c</mi><mi>p</mi></mrow></msub><mrow><mo>(</mo><mi>ω</mi><mo>,</mo><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span> indicate that the formation of Cooper pairs in this compound is highly probable within the energy interval 0–35 meV, where significant vibrational contributions to phonon dispersion arise from both Mg and B atoms. Moreover, the parameters <span><math><msub><mrow><mi>ω</mi></mrow><mrow><mi>c</mi><mi>p</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>N</mi></mrow><mrow><mi>c</mi><mi>p</mi></mrow></msub></math></span> obtained from <span><math><mrow><msub><mrow><mi>D</mi></mrow><mrow><mi>c</mi><mi>p</mi></mrow></msub><mrow><mo>(</mo><mi>ω</mi><mo>,</mo><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span> accurately replicate the pressure dependence of the superconducting critical temperature T<span><math><msub><mrow></mrow><mrow><mi>c</mi></mrow></msub></math></span> observed in MgB<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>. This provides a possible phenomenological explanation for its highest experimentally measured T<span><math><msub><mrow></mrow><mrow><mi>c</mi></mrow></msub></math></span>. An electronic analysis of <span><math><mrow><msub><mrow><mi>D</mi></mrow><mrow><mi>c</mi><mi>p</mi></mrow></msub><mrow><mo>(</mo><mi>ω</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> function below the Fermi level reveals initial consistency with both theoretical and experimental results for the superconducting gap energy in MgB<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>. These findings demonstrate that <span><math><mrow><msub><mrow><mi>D</mi></mrow><mrow><mi>c</mi><mi>p</mi></mrow></msub><mrow><mo>(</mo><mi>ω</mi><mo>,</mo><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span> is a promising theoretical tool for studying conventional superconductors.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"632 ","pages":"Article 1354677"},"PeriodicalIF":1.3,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143621485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Superconducting correlations in the asymmetric Hubbard model","authors":"Pavol Farkašovský","doi":"10.1016/j.physc.2025.1354693","DOIUrl":"10.1016/j.physc.2025.1354693","url":null,"abstract":"<div><div>The projector Quantum-Monte-Carlo method is used to examine effects of down-spin electron hopping <span><math><msub><mrow><mi>t</mi></mrow><mrow><mi>↓</mi></mrow></msub></math></span> and the on-site interaction <span><math><mi>U</mi></math></span> between the up and down spin electrons on superconducting correlations in the two-dimensional asymmetric Hubbard model. It is shown that both, the down-spin electron hopping, as well as the on-site interaction strongly enhance the superconducting correlations in the <span><math><mi>d</mi></math></span>-wave channel. The most significant enhancement of superconducting correlations, by down-spin electron hopping, is found for electron concentrations near the half-filled band case where, in addition, the strong connection between the diagonal charge stripes and the superconducting correlations is observed and the increasing on-site interaction <span><math><mi>U</mi></math></span> further enhances this effect. The enhancement of superconducting correlations is observed also in the axial striped phase, while it is negligible in the segregated phase. This opens new route to understanding the relation between the inhomogeneous charge ordering and superconductivity in strongly correlated electron systems.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"632 ","pages":"Article 1354693"},"PeriodicalIF":1.3,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143644296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"The significance of “stripes” in the physics of the cuprates, the Hubbard model, and other highly correlated electronic systems","authors":"Thomas P. Devereaux ,&nbsp;Steven A. Kivelson","doi":"10.1016/j.physc.2025.1354683","DOIUrl":"10.1016/j.physc.2025.1354683","url":null,"abstract":"<div><div>“Stripes”— meaning unidirectional charge-density-waves, sometimes (but not always) accompanied by spin-density-waves with twice the period - are now known to arise in broad swathes of the cuprate phase diagram, and appear as a strong ordering tendency in numerical studies of Hubbard-like models of highly correlated electron systems. Jan Zaanen’s work played a seminal role in predicting their existence, and exploring their possible significance. They are <em>not</em> related to any weak-coupling physics associated with some form of Fermi-surface nesting. And whether one likes them or not, they are surprisingly difficult to avoid; in the Hubbard model, for example, they often appear as an alternative order that can out-compete the otherwise favored <span><math><mi>d</mi></math></span>-wave superconductivity.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"632 ","pages":"Article 1354683"},"PeriodicalIF":1.3,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143562705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Holographic Schwinger–Keldysh effective field theories including a non-hydrodynamic mode","authors":"Yan Liu ,&nbsp;Ya-Wen Sun ,&nbsp;Xin-Meng Wu","doi":"10.1016/j.physc.2025.1354701","DOIUrl":"10.1016/j.physc.2025.1354701","url":null,"abstract":"<div><div>We derive the Schwinger–Keldysh effective field theories for diffusion including the lowest non-hydrodynamic degree of freedom from holographic Gubser–Rocha systems. At low temperature the dynamical non-hydrodynamic mode could be either an IR mode or a slow mode, which is related to IR quantum critical excitations or encodes the information of all energy scales. This additional dynamical vector mode could be viewed as an ultraviolet sector of the diffusive hydrodynamic theory. We construct two different effective actions for each case and discuss their physical properties. In particular we show that the Kubo–Martin–Schwinger symmetry is preserved.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"632 ","pages":"Article 1354701"},"PeriodicalIF":1.3,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143734575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 extrinsic parameters on superconducting nanowire single-photon detector output – A study towards developing read-out circuit","authors":"Amit Soni ,&nbsp;Anish M. Bhargav ,&nbsp;Pratiksha Pratap ,&nbsp;V.N. Singh","doi":"10.1016/j.physc.2025.1354689","DOIUrl":"10.1016/j.physc.2025.1354689","url":null,"abstract":"<div><div>A superconducting nanowire single-photon detector (SNSPD) is an optoelectrical device that works on the concept of hotspot formation and can detect a single photon. The associated readout circuit plays a vital role in determining the response of SNSPD. The available resources, complexity, and costs are major limiting factors in the actual readout circuit design. The preliminary information about the extrinsic effects that alter the SNSPD output from its desired value helps fabricate readout circuits. Here, the electrical equivalent circuit (EEC) for SNSPD has been simulated using LT spice software, and accordingly, a model has been developed to understand the readout circuit requirements. The EEC has been tested at room temperature by varying parameters like pulse width, bias voltage, capacitance and inductance. In addition, we have also designed and simulated a circuit for the multi-pixel photon counting scheme using a frequency multiplexing technique. Utilising this scheme, we observed that each EEC could be distinguished by its unique resonance frequency, reducing circuit complexity and power consumption. The results obtained indicate that their unique resonance frequency can identify triggered EEC.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"632 ","pages":"Article 1354689"},"PeriodicalIF":1.3,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143579416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 winding pitches on dynamic resistance of CICC made from CORCs","authors":"Liguang Hu ,&nbsp;Xuhui Xu ,&nbsp;Bibo Zhou ,&nbsp;Xian Chen ,&nbsp;Qi Cheng ,&nbsp;Bangzhu Wang ,&nbsp;Junhua Cheng","doi":"10.1016/j.physc.2025.1354681","DOIUrl":"10.1016/j.physc.2025.1354681","url":null,"abstract":"<div><div>The second generation (2G) high temperature superconducting (HTS) REBCO tapes, presently a unique possible candidate for use in future large high field magnets above 25 T, are promising choice for high capacity current cable-in-conduit conductor (CICC) used in large high field magnets of fusion and power transmissions. Generally, HTS based CICCs are made from several HTS cables or strands consisting of individual REBCO tapes. A configuration of CICC is proposed, which is made from six conductor on round core cables (CORCs) with symmetrically helical winding on a petal copper former. The cooling medium flows in central channels of former and six CORCs, respectively. Although the CICCs generally operate in DC mode, they inevitable endure AC influence at least in charging and discharging process or even ripple current. Consequently, the dynamic resistance appears, which not only generates additional AC loss but also importantly causes nonuniform current distribution and instability. This paper employs analytical model and numerical simulations to investigate the dynamic resistance characteristics of CORC and CICC conductors with different winding pitches respectively. An analytical model is established based on the rotating magnetic field method to efficiently compute the dynamic resistance of single-layer CORC and CICC. Subsequently, three-dimensional (3D) models of CORC and CICC with different winding pitches are established. Using finite element method, the influence of winding pitches on dynamic resistance are calculated based on the T-A formulation. Numerical simulation results are consistent with analytical calculations, demonstrating that winding pitch has a significant impact on dynamic resistance. This study can provide valuable reference for the design of large-scale high field magnets.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"631 ","pages":"Article 1354681"},"PeriodicalIF":1.3,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143600854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 temperature and spinning speed on texture in spin-coated Sm2Zr2O7 buffer layer on Ni-5 at.%W RABiTS for coated conductors","authors":"M. Nandana Nandakumar ,&nbsp;Rahul Raj ,&nbsp;M.S. Ramachandra Rao ,&nbsp;Deepak Kumar ,&nbsp;Satyam Suwas ,&nbsp;N. Harish Kumar","doi":"10.1016/j.physc.2025.1354669","DOIUrl":"10.1016/j.physc.2025.1354669","url":null,"abstract":"<div><div>The usage of Rolling Assisted Biaxially Textured Substrates (RABiTS) is a versatile method to produce High-Temperature Superconductor (HTS) based coated conductors. We have investigated, for the first time, the texture evolution of the Sm₂Zr₂O₇ (SZO) barrier layer produced by spin coating on Ni-5 at.%W (Ni5W) RABiTS to create a biaxially textured buffer layer architecture. The annealing temperature and spinning speed which are the important film deposition parameters, were varied and their effect on the texture of the film has been investigated to obtain the optimum conditions required for the growth of highly textured film with sufficient thickness. Textured growth of SZO film could be seen across a wide range of substrate temperatures by X-ray diffraction (XRD) based studies. The microstructural investigations were executed using a Scanning Electron Microscope (SEM) and Atomic Force Microscope (AFM). The findings indicate that the annealing temperature and spinning speed affect the films' growth orientation and surface morphology. The XRD (φ scan and ω scan) studies have shown the ability to realise the SZO buffer layer with strong in-plane and out-of-plane texture and a c-axis oriented growth on Ni5W substrate by chemical solution deposition (CSD).</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"631 ","pages":"Article 1354669"},"PeriodicalIF":1.3,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143600852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}