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ISSN: 2772-8307
Copyright © 2026 Shanghai Jiaotong University. Published by Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
Abstract
Corresponding email:jld35@cam.ac.uk
The factors that influence high-field, low-temperature current carrying performance of coated conductors are complex. Using epitaxial thin films grown by pulsed laser deposition (PLD) made from (RE’RE”)Ba2Cu3 O (YREBCO), where RE = rare earth targets, with and without liquid (L) additions, this work decouples the different complex effects (both positive and negative) of RE mixing. In doing so, we understand the outcomes of the separate effects of this mixing, and the incidental formation of (Y,RE’,RE”)2O3 nanoparticles. The YREBCO composition is chosen because it permits growth conditions to be the same and near-optimum for all the targets, i.e., at the optimum temperature as for the growth of pure YBCO, the reference composition, to enable effective comparison of compositions. We find that a high RE ion size variance increases the RE2O fraction but that (20 K, 8 T) is decreased, owing to the associated atomic disorder. On the other hand, we find that for moderate variance (and moderate RE2O3 nanoparticle formation), (20 K, 8 T) is increased. A liquid phase needs to be included to ensure minimal microstructural disorder of the YREBCO lattice caused by the RE2O nanoparticle inclusions. Of the wide range of PLD target compositions explored, (GdYb)Ba2Cu3O is determined to have the optimum moderate ion size variance. An approximate doubling of (20 K, 8 T) compared to pure YBCO films results. Thus, the (GdYb)Ba2Cu3O composition with extra liquid phase addition represents an ideal base composition to which artificial pinning centres (APC) can be added for further enhancement.
cited:0
Anisotropy modulation and band structure reconstruction induced by high pressure in Kagome metal GdV6Sn6
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Article Number:Article 100174
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Abstract
Corresponding email:yangxiaofan@fudan.edu.cn
The geometric frustrations and unique electronic structures in Kagome lattices normally give rise to various quantum matter ground states. V-based Kagome compounds, such as AV3Sb5, exhibit a complex phase diagram under hydrostatic pressure modulation. Herein, we report an electronic structure evolution in another novel V-Kagome system RV6Sn6, with pressures changing from 0 to 107 GPa, through density functional calculations. Our results reveal that the electronic density of GdV6Sn6 exhibits pronounced anisotropy under high pressures. Specifically, electronic structure instabilities stem from van Hove singularities are observed in the V-Kagome plane, while that remains robust up to approximately 40 GPa in the M momentum space. In the high-pressure regime (107 GPa), the newly formed saddle point approaches and crosses the Fermi level, enhancing the density of states (DOS) at the Fermi level. This potentially results in pressure-induced superconductivity, accompanied by the formation of charge channels. Our findings provide essential insights into the electronic structure of GdV6Sn6 under high pressures, offering a valuable model for investigating V-Kagome physics in RV6Sn6 compounds.
cited:8
High critical current double-sided, thick-film REBa2Cu3O7−δ tapes by Advanced MOCVD
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Article Number:Article 100184
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Abstract
Corresponding email:tmqu@mail.tsinghua.edu.cn
Enhancing the cost-effectiveness and performance of Rare Earth Barium Copper Oxide (REBCO) coated conductors remains a key objective for advancing applications in power transmission, fusion energy, particle accelerators, and rotating machines. One direct method to achieve this is by increasing the conductor’s critical current under operational conditions. This study introduces a major breakthrough in fabricating Zr-doped (Gd,Y) BaCuO double-sided tapes utilizing an Advanced Metal Organic Chemical Vapor Deposition (A-MOCVD) technique. A single-pass deposition resulted in uniform films of on both sides of the tape, with critical current values at 20K and 20T consistently above 950 A/4 mm, peaking at 1100 A/4 mm. Additionally, a self-field transport critical current of 930 A/4 mm was attained in self-field conditions at 77 K, 0 T, translating to a critical current density of 2.9 MA/cm 2. These results represent some of the highest reported performance metrics for REBCO tapes of this thickness, underscoring the potential of double-sided A-MOCVD processing for next-generation superconducting applications.
cited:9
Critical current degradation of REBCO coated conductor tapes caused by multiple cracks under tensile loading
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Article Number:Article 100185
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Abstract
Corresponding email:tmqu@mail.tsinghua.edu.cn
REBa2Cu3Ox (REBCO) coated conductors exhibit irreversible critical current () degradation under tensile strain beyond the irreversible strain (). While this degradation is attributed to cracking, the specific crack evolution process and its quantitative relation to degradation remain unclear. Here, the multiplication of cracks in REBCO tapes under tensile is characterized. It was found that surface particles disrupt continuous crack propagation, causing fragmentation of the REBCO layer. A shear lag model describes how the stress distribution evolves with fragmentation spacing. A probabilistic fracture model then predicts the two-regime spacing reduction as a function of applied strain. The discontinuous crack network acts as the residual flow channel for current once strain exceeds . Crack spacing determines the remaining in this regime. An analytical model is thus proposed to capture the degradation behavior based on the quantified fragmentation process. Additionally, this study suggests approaches to obtain a wider safe operating strain range through tailoring of the fracture behavior, expanding the practical application limits. This work provides new insights into the progressive cracking mechanisms governing irreversible degradation in strained REBCO tapes.
cited:0
Enhanced-performance superconducting nanowire avalanche photodetector with staggered bends
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Article Number:Article 100186
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Abstract
Corresponding email:ldkong@mail.sim.ac.cn; lxyou@mail.sim.ac.cn
Emerging quantum technologies and weak-light applications demand photon detectors with a simultaneously high counting rate and near-unity efficiency. Superconducting nanowire single-photon detectors can achieve >90% system detection efficiency, but maintaining this efficiency at high counting rates remains challenging. Although parallel-configured superconducting nanowire avalanche photodetectors (SNAPs) reduce the recovery time, their designs intensify the current crowding effects at bends, leading to persistent challenges in achieving high system detection efficiency. We developed an optimized bend structure for meandered parallel nanowires called staggered bends, which increased the switching current by 11.3% in the 2-SNAPs. At 1064 nm, the optimized 2-SNAP and 3-SNAP with staggered bends achieved system detection efficiencies of 96.6% and 98.1%, respectively. Meanwhile, these devices maintain 90% system detection efficiency while achieving counting rates of 3.1 MHz and 10.3 MHz. This study establishes a practical framework for SNAPs with demonstrated performance metrics that could enable advancements in the frontiers of quantum information.
cited:9
Pressure-driven charge transfer and tunable superconductivity in intermetallic Li–Mg electrides
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Article Number:Article 100187
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Abstract
Corresponding email:zhangxh318@ysu.edu.cn; yanggc468@nenu.edu.cn
Electrides, materials in which a portion of valence electrons reside as interstitial anionic electrons (IAEs) within lattice cavities—exhibit a wide range of extraordinary physical and chemical properties, making them a central focus of condensed matter physics. Under high pressure, intermetallic systems provide a unique pathway to novel electrides by enabling unconventional charge-transfer mechanisms. Here, we employ first-principles structure searches to identify two stable Li-Mg electrides, Li3Mg and Li4Mg. At low pressure, Mg atoms act as anionic centers through occupation of their outer-shell 3p orbitals. Upon compression, charge is transferred from Mg to the lattice cavities, enhancing the localization and density of IAEs. This, in turn, strengths electron–phonon coupling and raises the superconducting transition temperature () to 13.3 K at 75 GPa for Li3Mg and 19.7 K at 80 GPa for Li4Mg—values that surpass most known electride superconductors below 100 GPa. Selective hydrogen insertion into the lattice cavities in Li4Mg quenches the IAEs and confirms their essential role in superconductivity. Further compression drives a transition to poor or non-superconducting phases, with Mg atoms switching from electron acceptors to donors, contrary to the typical behavior of electropositive metals, which tend to transition from donors into acceptors under pressure. These findings highlight the pivotal role of IAEs in electride superconductivity and pave the way for designing novel intermetallic electrides with tunable properties.
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