Strong anomalous proximity effect from spin-singlet superconductors
Satoshi Ikegaya, Jae‐Chul Lee, Andreas P. Schnyder, Yasuhiro Asano
Abstract
The proximity effect from a spin-triplet ${p}_{x}$-wave superconductor to a dirty normal-metal has been shown to result in various unusual electromagnetic properties, reflecting a cooperative relation between topologically protected zero-energy quasiparticles and odd-frequency Cooper pairs. However, because of a lack of candidate materials for spin-triplet ${p}_{x}$-wave superconductors, observing this effect has been difficult. In this paper, we demonstrate that the anomalous proximity effect, which is essentially equivalent to that of a spin-triplet ${p}_{x}$-wave superconductor, can occur in a semiconductor/high-${T}_{c}$ cuprate superconductor hybrid device in which two potentials coexist: A spin-singlet $d$-wave pair potential and a spin-orbit coupling potential sustaining the persistent spin-helix state. As a result, we propose an alternative and promising route to observe the anomalous proximity effect related to the profound nature of topologically protected quasiparticles and odd-frequency Cooper pairs.