Three-Gap High-<i>T</i><sub>c</sub> Topological Superconductivity in Lithium-Doped Bilayer Borophenes.

Wang, Meng-Hui; Wang, Zheng-Xuan; Song, Hao-Lin; Wang, Guang-Tao; Cui, Zhong-Hua · Nano Lett · 2025

basic_science · Level V

Where this comes from

Abstract

Realizing topological superconductors (TSCs) with high transition temperatures (high-<i>T</i><sub>c</sub>) remains a central challenge in the development of fault-tolerant quantum computation. Here, we propose a route for realizing high-<i>T</i><sub>c</sub> TSCs by integrating multigap superconductivity with nontrivial band topology in lithium-doped bilayer borophene. Extensive structural searches and high-throughput screening of over 4000 Li<sub>1-<i>x</i></sub>B<sub><i>x</i></sub> nanosheets identify eight promising multigap TSC candidates. Among them, the LiB<sub>12</sub> nanosheet is identified as a prototypical three-gap superconductor and simultaneously a topological metal with a symmetry-protected Dirac nodal loop. Fully anisotropic Migdal-Eliashberg calculations reveal cooperative couplings between σ↔in-plane and π↔out-of-plane phonon, which markedly enhance electron-phonon interactions and drive a high-<i>T</i><sub>c</sub> of 57 K. These findings underscore the potential of metal-doped bilayer borophenes as a cutting-edge material platform for achieving high-<i>T</i><sub>c</sub> multigap TSCs.