Superconducting diode effect under time reversal symmetry

TL;DR

This paper demonstrates strain-controlled superconducting diode effects in PbTaSe2, revealing intrinsic SDE under time-reversal symmetry and highlighting the role of strain-induced electric polarization.

Contribution

It provides experimental evidence of intrinsic superconducting diode effect under time-reversal symmetry, controlled by strain in a layered superconductor.

Findings

SDE appears only in strained devices

Zero-field and magnetic field-even/odd SDE observed

Strain-induced electric polarization is crucial

Abstract

In noncentrosymmetric superconductors, superconducting and normal conductions can interchange based on the current flow direction. This effect is termed a superconducting diode effect (SDE), which is a focal point of recent research. The broken inversion and time reversal symmetry is believed to be the requirements of SDE but their intrinsic role has remained elusive. Here, we report strain-controlled SDEs in a layered trigonal superconductor, PbTaSe2. The SDE was found exclusively in a strained device with its absence in an unstrained device, despite that it is allowed in unstrained trigonal structure. Moreover, the zero-field or magnetic field-even (magnetic field-odd) SDE is observed when the strain and current are along armchair (zigzag) direction The results unambiguously demonstrate the intrinsic SDE under time-reversal symmetry and the critical role of strain-induced electric polarization.