Physica C-superconductivity and Its Applications最新文献

{"title":"Does the Meissner effect require radial charge flow?","authors":"J.E. Hirsch","doi":"10.1016/j.physc.2025.1354724","DOIUrl":"10.1016/j.physc.2025.1354724","url":null,"abstract":"<div><div>The conventional theory of superconductivity is believed to account for the Meissner effect without radial charge flow. Instead, we have argued in earlier work that the Meissner effect is impossible in the absence of radial flow of charge because of Alfven’s theorem. Here I discuss different sample geometries that could help to determine experimentally whether or not radial charge flow is necessary for superconductors to expel magnetic fields.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"633 ","pages":"Article 1354724"},"PeriodicalIF":1.3,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143903791","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":"Stripe-like correlations in the cuprates from oxygen NMR","authors":"Daniel Bandur ,&nbsp;Abigail Lee ,&nbsp;Stefan Tsankov ,&nbsp;Andreas Erb ,&nbsp;Jürgen Haase","doi":"10.1016/j.physc.2025.1354722","DOIUrl":"10.1016/j.physc.2025.1354722","url":null,"abstract":"<div><div>Nuclear magnetic resonance (NMR) of planar oxygen, with its family independent phenomenology, is ideally suited to probe the nature of the quantum matter of superconducting cuprates. Here, with new experiments on La<span><math><msub><mrow></mrow><mrow><mn>2</mn><mo>−</mo><mi>x</mi></mrow></msub></math></span>Sr<span><math><msub><mrow></mrow><mrow><mi>x</mi></mrow></msub></math></span>CuO<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span>, in particular also at high doping levels, we report on short-range stripe-like correlations between local charge and spin. The amplitudes of the spin and charge variations at room temperature are nearly independent of doping up to at least <span><math><mrow><mi>x</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>30</mn></mrow></math></span>. However, the correlation is inverted upon passing <span><math><mrow><mi>x</mi><mo>=</mo><mn>1</mn><mo>/</mo><mn>4</mn></mrow></math></span>. Despite the atomic scale length, the variations still resemble the average spin and charge relation. Literature data show the correlations to be generic to the cuprates.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"633 ","pages":"Article 1354722"},"PeriodicalIF":1.3,"publicationDate":"2025-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143900335","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":"Concealed Mott criticality: Unifying the Kondo breakdown and doped charge-transfer insulators","authors":"Louk Rademaker","doi":"10.1016/j.physc.2025.1354720","DOIUrl":"10.1016/j.physc.2025.1354720","url":null,"abstract":"<div><div>I show that the quantum critical points observed in heavy fermions (the ‘Kondo breakdown’) and in doped cuprates can be understood in terms of concealed Mott criticality. In this picture, one species of electrons undergoes a Mott localization transition, in the presence of metallic charge carries. As is shown in a simple toy model, this results in a Fermi surface jump at the transition, as well as mass enhancement on both the ‘large’ and ‘small’ Fermi surface side of the transition, consistent with the experimental observations.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"633 ","pages":"Article 1354720"},"PeriodicalIF":1.3,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143887603","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":"Mixed-symmetry superconductivity and the energy gap","authors":"P. Senarath Yapa ,&nbsp;X. Guo ,&nbsp;J. Maciejko ,&nbsp;F. Marsiglio","doi":"10.1016/j.physc.2025.1354719","DOIUrl":"10.1016/j.physc.2025.1354719","url":null,"abstract":"<div><div>The symmetry of the superconducting order parameter, or simply the “gap”, provides certain constraints on the actual mechanism that gives rise to pairing and ultimately to superconductivity. In this work we show how superconducting phases with mixed singlet-triplet symmetries can arise below <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span> for a generic tight-binding model. We first examine the 1D case to better illustrate the prevalence of symmetry-breaking transitions below <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span>, and then the more realistic 2D case. In both cases we illustrate the implication for spectroscopic investigations of the energy gap by calculating the density of states for different temperatures below <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span>. We find that the structure of the density of states near <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span> can vary dramatically from its form near <span><math><mrow><mi>T</mi><mo>=</mo><mn>0</mn></mrow></math></span>. A complete picture of the superconducting symmetry can only be attained if measurements are made over the entire temperature range.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"633 ","pages":"Article 1354719"},"PeriodicalIF":1.3,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143904196","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":"Elastoplastic contact behavior of multi-stage superconducting cables under tension","authors":"Zhiwen Zhou,&nbsp;Sitongyan Li,&nbsp;Zhiwen Gao","doi":"10.1016/j.physc.2025.1354727","DOIUrl":"10.1016/j.physc.2025.1354727","url":null,"abstract":"<div><div>The superconductor cable with multi-stage twisted strands is a key component in the International Thermonuclear Experimental Reactor. These superconducting strands are composite materials with a complex microstructure. In the study, an elastoplastic constitutive model incorporating both isotropic and kinematic hardening is established to investigate the mechanical properties of the strands. The model is implemented as a user-defined material subroutine (UMAT) in the commercial finite element code ABAQUS using the fully implicit backward Euler method. Based on the analysis of the elastoplastic properties of the strands, a numerical contact model is developed to predict the contact characteristics of the multi-stage superconducting cable. The influence of helical pitch on the contact characteristics is examined by integrating the elastoplastic constitutive relations of the strands with their hierarchical helical structures. Numerical results demonstrate that the proposed model accurately describes the contact characteristics of the multi-stage superconducting cable. It is noteworthy that the elastoplastic contact force is found to be smaller than the elastic contact force. This elastoplastic contact model can be effectively used to predict the degradation of critical current in the multi-stage superconducting cable due to tensile loads.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"633 ","pages":"Article 1354727"},"PeriodicalIF":1.3,"publicationDate":"2025-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143859871","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":"Praseodymium doping effect on the superconducting properties of FeSe0.5Te0.5 bulks under ambient and high-pressure growth conditions","authors":"Priya Singh ,&nbsp;Manasa Manasa ,&nbsp;Mohammad Azam ,&nbsp;Tatiana Zajarniuk ,&nbsp;Svitlana Stelmakh ,&nbsp;Taras Palasyuk ,&nbsp;Jan Mizeracki ,&nbsp;Tomasz Cetner ,&nbsp;Andrzej Morawski ,&nbsp;Cezariusz Jastrzębski ,&nbsp;Michał Wierzbicki ,&nbsp;Shiv J. Singh","doi":"10.1016/j.physc.2025.1354729","DOIUrl":"10.1016/j.physc.2025.1354729","url":null,"abstract":"<div><div>A series of Pr-doped FeSe_0.5Te_0.5 (Fe_1-<em>_x</em>Pr<em>_x</em>Se_0.5Te_0.5; <em>x</em> = 0 to 0.3) bulks are prepared by conventional synthesis process at ambient pressure (CSP), and high gas pressure and high temperature synthesis (HP-HTS) methods. These bulks are well characterized by structural and microstructural analysis, Raman spectroscopy, transport, and magnetic measurements. The HP-HTS process of the parent bulks has enhanced the onset transition temperature (<em>T_c^onset</em>) by 1.5 K and the critical current density (<em>J_c</em>) by two orders of magnitude compared to the CSP method. Pr-doped FeSe_0.5Te_0.5 up to 10 % doping content prepared, either CSP or HP-HTS, slightly increases the unit cell volume, and high-pressure growth produces an almost pure superconducting phase, which confirms the successful Pr-doping at Fe sites. Raman spectroscopy measurements and DFT calculations suggest the substitution of Pr-atoms in the interlayer spacing of Fe(Se,Te) lattice. High-pressure growth of Fe_1-<em>_x</em>Pr<em>_x</em>Se_0.5Te_0.5 also makes the sample less dense compared to the parent sample grown by HP-HTS. Transport and magnetic measurements depict that <em>T_c^onset</em> is almost unaffected by Pr-doping, whereas <em>J_c</em> of Pr-doped FeSe_0.5Te_0.5 is enhanced by one order of magnitude relative to the parent sample developed by CSP but lower than that of the parent sample grown by HP-HTS. Hence, Pr- doping at Fe sites preserves <em>T_c^onset</em> and improves <em>J_c</em> of FeSe_0.5Te_0.5 regardless of the doping contents and growth conditions. These results are promising for the practical application of iron-based superconductors to improve <em>J_c</em> properties without affecting <em>T_c^onset</em> through CSP process and congruent with discoveries from other superconductors, like cuprates and MgB₂.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"633 ","pages":"Article 1354729"},"PeriodicalIF":1.3,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869290","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":"Glassy relaxation and weak vortex pinning in anisotropic (Ca0.85La0.15)10(Pt3As8)(Fe2As2)5 single crystals","authors":"N. Haberkorn ,&nbsp;Yong Seung Kwon","doi":"10.1016/j.physc.2025.1354726","DOIUrl":"10.1016/j.physc.2025.1354726","url":null,"abstract":"<div><div>We present a comprehensive study on the vortex dynamics of (Ca_0.85La_0.15)₁₀(Pt₃As₈)(Fe₂As₂)₅ ​ single crystals, characterized by magnetization measurements. With a superconducting critical temperature of 32 K, this material is notable for its substantial anisotropy (5–6), which significantly influences the intrinsic vortex fluctuations. Our results reveal low critical current densities, i. e. <em>J_c</em>∼0.6 MA/cm² at 1.8 K and low magnetic fields. The magnetic field dependences of <em>J_c</em> exhibit a fishtail or second peak in the magnetization, a feature commonly associated with weak vortex pinning and vortex relaxation crossovers. Moreover, the flux creep rates are exceptionally large at low fields and temperatures. Through Maley’s analysis, we extract low vortex pinning energies (∼50 K) and glassy exponents that are consistent with expectations for single-vortex pinning, progressively evolving towards vortex bundles. These findings enhance our understanding of vortex dynamics in iron-based superconductors, highlighting the key role of intrinsic vortex fluctuations in the vortex phase diagram.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"633 ","pages":"Article 1354726"},"PeriodicalIF":1.3,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143878676","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 doping on spin density wave & superconductivity in electron-doped iron Pnictide superconductors","authors":"Santosh Kumar Barik ,&nbsp;Barada Priyadarsini Tarai ,&nbsp;Basanta Kumar Sahoo ,&nbsp;Bibekananda Panda","doi":"10.1016/j.physc.2025.1354705","DOIUrl":"10.1016/j.physc.2025.1354705","url":null,"abstract":"<div><div>We formulate a Hamiltonian model to investigate the effects of doping on superconductivity and spin density wave in electron-doped iron pnictide superconductors. The model, which is based on the BCS mechanism, employs a mean-field approach. The equations of motion for single-particle electron Green’s functions are derived from Zubarev type electron Green’s function. Single-particle correlation functions were derived by analysing the quasi-particle energies. The superconducting (SC) gap (z), spin density wave (SDW) gap (h) and chemical potential (<span><math><mi>μ</mi></math></span>) were determined self-consistently and numerically for various dopant concentrations (x). The results indicate that as doping levels increase, the SDW gradually weakens, leading to the onset of superconductivity. In the doping range <span><math><mrow><mi>x</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>045</mn><mo>−</mo><mn>0</mn><mo>.</mo><mn>06</mn></mrow></math></span>, a coexistence of the SDW and superconductivity is observed. Further doping results in the suppression of the spin density wave, accompanied by a rise in the superconducting critical temperature, which reach 26 K at <span><math><mrow><mi>x</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>07</mn></mrow></math></span>. The phase diagram depicting the relationship between the SDW Neel Temperature, SC critical temperature and doping parameter agrees well with experimental observations.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"633 ","pages":"Article 1354705"},"PeriodicalIF":1.3,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143817714","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 foot, the fan, and the cuprate phase diagram: Fermi-volume-changing quantum phase transitions","authors":"Subir Sachdev","doi":"10.1016/j.physc.2025.1354707","DOIUrl":"10.1016/j.physc.2025.1354707","url":null,"abstract":"<div><div>A Fermi liquid with a ‘large’ Fermi surface (FL) can have a quantum phase transition to a spin density wave state (SDW) with reconstructed ‘small’ Fermi pockets. Both FL and SDW phases obey the Luttinger constraints on the volume enclosed by the Fermi surfaces. Critical spin fluctuations lead to spin-singlet <span><math><mi>d</mi></math></span>-wave pairing, as observed in the cuprates. Studies of the influence of spatial disorder on the FL-SDW quantum phase transition predict an extended quantum-critical Griffiths-type phase at low temperatures on the large Fermi surface side. These computations agree with the ‘foot’ of strange metal transport, and recent low temperature neutron scattering observations on La<span><math><msub><mrow></mrow><mrow><mn>2</mn><mo>−</mo><mi>x</mi></mrow></msub></math></span>Sr<span><math><msub><mrow></mrow><mrow><mi>x</mi></mrow></msub></math></span>CuO<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span>.</div><div>However, this theory cannot explain the higher temperature pseudogap and the ‘fan’ of strange metal behavior of the hole-doped cuprates. Here we need to consider underlying Fermi-volume-changing quantum phase transitions without symmetry breaking. Then the small Fermi surface phase does not obey the Luttinger constraint, and the pseudogap metal is described by thermal fluctuations above a ‘fractionalized Fermi liquid’ (FL*) or a ‘holon metal’, with the descriptions related by a duality on a background spin liquid. The quantum critical fan is described using a field theory for an underlying FL-FL* quantum phase transition in the presence of spatial disorder. This field theory can be mapped to a form which can be analyzed using the methods of the Sachdev–Ye–Kitaev model. Such an analysis successfully models linear-in-temperature resistivity, optical conductivity and thermopower observations in the quantum critical fan.</div><div>The confinement crossover connecting these lower and higher temperature descriptions is also discussed.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"633 ","pages":"Article 1354707"},"PeriodicalIF":1.3,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143839000","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":"Dependence of the energy and orbital structure of local states in CuO monolayer on Coulomb parameters","authors":"I.A. Makarov,&nbsp;M.M. Korshunov,&nbsp;S.G. Ovchinnikov","doi":"10.1016/j.physc.2025.1354706","DOIUrl":"10.1016/j.physc.2025.1354706","url":null,"abstract":"<div><div>The dependence of the energies and orbital structure of local states in the CuO monolayer on intra- and interatomic Coulomb interactions on copper and oxygen orbitals is studied. The electronic system is described within the eight-band <span><math><mrow><mi>p</mi><mo>−</mo><mi>d</mi></mrow></math></span> model in the hole representation with the on-site energies and hopping integrals obtained using density functional theory. CuO cluster multiparticle eigenstates are calculated using exact diagonalization. The difference between the energy dependencies on the Coulomb parameters for the states with the predominant probability density on the <span><math><mi>d</mi></math></span>-orbital and the states in which hole occupies <span><math><mi>p</mi></math></span>-orbitals leads to crossover of <span><math><mi>d</mi></math></span>- and <span><math><mi>p</mi></math></span>-states. The ground single-hole and two-hole states which determine the electronic structure of the low-energy excitations have the character of <span><math><mi>d</mi></math></span>- or <span><math><mi>p</mi></math></span>-orbitals in the different regions of the Coulomb parameters space. The gap between the energies of the dispersionless quasiparticles forming the top of the valence band and conductivity band also have different values in these two regions. The magnitude of this gap and the orbital character of the local multiparticle states change sharply even with an insignificant change in the Coulomb interactions within the boundary region of parameters between the regions in which the local states are formed by the <span><math><mi>d</mi></math></span>- or <span><math><mi>p</mi></math></span>-orbitals.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"633 ","pages":"Article 1354706"},"PeriodicalIF":1.3,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800455","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}