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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.
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.
cited:19
Commercial compact fusion triggered REBCO tape industry: Pulsed laser deposition technology opportunities and challenges
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Article Number:Article 100188
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Abstract
Corresponding email:yuezhao@sjtu.edu.cn
The rapid rise of commercial compact fusion devices has triggered fast-growing demand for high-temperature superconducting tapes, creating a major opportunity for the high-temperature superconducting (HTS) tape industry. Pulsed laser deposition (PLD) has been extensively applied for fabrication of heteroepitaxial HTS wires or tapes based on REBCO-type superconductor, also referred to as, coated conductors (CCs). A combination of multi-plume, multi-turn deposition technique and use of high-power excimer lasers has enabled and accelerated the industrialization of REBCO coated conductors. Currently, the annual production of top-tier PLD-based, HTS-wire manufacturers exceeds 3,000 km-12 mm, contributing to over half of the total global HTS wire production. PLD-REBCO tapes have demonstrated excellent in-field performance ( > 200 A-4 mm @20K, 20T, B//c) and competitive pricing ($20/m). PLD technology continues to evolve, demonstrating strong competitive advantages. However, challenges remain in further cost reduction, process stability, and increasing efficiency of raw material utilization. AI-based data mining and tackling emerging fundamental issues are seen as potential solutions to further improve stability and performance.
cited:11
High temperature superconductor coated conductors: A highly complex system where the only way is ‘ups’
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Article Number:Article 100189
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cited:11
High performance multifactorial designs based on a refined analytical method for HTS maglev systems
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Article Number:Article 100190
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Corresponding email:deng@swjtu.cn
YBaCuO high-temperature superconductors (HTS) exhibit remarkable passive levitation over permanent magnet guideways (PMG), but the strong nonlinearity poses significant challenges for developing analytical models for HTS maglev systems. This paper presents a refined analytical method for calculating the electromagnetic force in such systems. The method incorporates critical factors, including the complex properties of the superconductors, the Halbach PMG geometry, and various operation conditions. The derived analytical expressions explicitly reveal the interplay between system parameters and levitation performance. Experimental and numerical validation confirms the model’s high prediction accuracy in magnetic fields, levitation and guidance forces. A sensitivity analysis further identifies the most influential parameters such as thickness of the magnet, levitation height, Halbach wavelength. Moreover, this paper calculates and provides the recommended structural parameters for both rare-earth and rare-earth-free PMG. The potential of HTS maglev systems for heavy-haul applications is explored, demonstrating the capability to achieve significant levitation force (about 50 ton/m) under constrained geometric conditions. This work provides critical insights for minimizing permanent magnet consumption in HTS maglev systems and circumventing rare-earth material constraints.
cited:12
A low-resistance joint of REBCO stacked cable for large-scale superconducting magnets
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Article Number:Article 100191
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Abstract
Corresponding email:songp@mail.tsinghua.edu.cn；tmqu@mail.tsinghua.edu.cn
The integration of REBCO superconducting coils into compact tokamak toroidal field magnets represents a transformative advancement in fusion technology. In the fabrication of these magnets, electrical connections between pancake coils are typically established through a transverse bridging joint, the performance of which critically impacts device efficiency. To address the demand for enhanced connectivity, this study presents a novel bridge-type “stacked joint” utilizing a superconducting-copper composite structure, optimized for inter-coil connections of stacked REBCO cables. Leveraging a modular stacking approach and low-temperature soldering, this design achieves a resistance as low as 1 over a 10 cm length alongside a soldering resistivity below 25 in a liquid nitrogen (77 K) self-field environment. The study further investigates the impact of tape length and quantity on joint electrical performance under this configuration. Rigorous testing, including 10 thermal cycles (77 K to room temperature) and pressure loads up to 30 MPa, confirms the joint’s structural reliability and the consistency of the fabrication process, underscoring its potential for fusion applications.
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