従来にない界面超伝導体が量子コンピューティングに役立つ可能性(Unconventional interface superconductor could benefit quantum computing)

2024-08-23 カリフォルニア大学リバーサイド校(UCR)

＜関連情報＞

• https://news.ucr.edu/articles/2024/08/23/unconventional-interface-superconductor-could-benefit-quantum-computing
• https://www.science.org/doi/10.1126/sciadv.ado4875

超伝導体-キラル物質のヘテロ構造におけるスピン活性界面と局所的に増強されたゼーマン場の特徴 Signatures of a spin-active interface and a locally enhanced Zeeman field in a superconductor-chiral material heterostructure

Cliff Chen, Jason Tran, Anthony McFadden, Raymond Simmonds, […], and Peng Wei
Science Advances  Published:23 Aug 2024
DOI:https://doi.org/10.1126/sciadv.ado4875

Abstract

A localized Zeeman field, intensified at heterostructure interfaces, could play a crucial role in a broad area including spintronics and unconventional superconductors. Conventionally, the generation of a local Zeeman field is achieved through magnetic exchange coupling with a magnetic material. However, magnetic elements often introduce defects, which could weaken or destroy superconductivity. Alternatively, the coupling between a superconductor with strong spin-orbit coupling and a nonmagnetic chiral material could serve as a promising approach to generate a spin-active interface. Here, we leverage an interface superconductor, namely, induced superconductivity in noble metal surface states, to probe the spin-active interface. Our results unveil an enhanced interface Zeeman field, which selectively closes the surface superconducting gap while preserving the bulk superconducting pairing. The chiral material, i.e., trigonal tellurium, also induces Andreev bound states (ABS) exhibiting spin polarization. The field dependence of ABS manifests a substantially enhanced interface Landé g-factor (g_eff ~ 12), thereby corroborating the enhanced interface Zeeman energy.