2021 年 56 巻 5 号 p. 277-282
Microscopic theory of the depairing current density (jd) is briefly reviewed for the applied-superconductivity communities. The goal of this article is to introduce the Kupriyanov-Lukichev-Maki theory of jd for s-wave superconductors in the diffusive limit, which is the most reliable calculation of jd based on the BCS theory and is relevant to various superconducting devices. The effect of subgap states on jd is also discussed.