Superconducting piezoelectric effect

TL;DR

This paper introduces the superconducting piezoelectric effect (SCPE), a novel phenomenon allowing piezoelectric responses in superconductors, which could enable new applications and insights into superconducting symmetries.

Contribution

It formulates the SCPE theoretically and calculates its magnitude, demonstrating its comparability to the magnetopiezoelectric effect in noncentrosymmetric superconductors.

Findings

SCPE magnitude is comparable to MPE.

Finite Cooper pair momentum is crucial for SCPE.

SCPE offers a new probe for superconducting symmetry.

Abstract

The magnetopiezoelectric effect (MPE) is a cross-coupling between an electric current and strain in metals with neither inversion symmetry nor time-reversal symmetry. Unlike the conventional piezoelectric effect, the MPE allows a piezoelectric response in superconductors, as we call the superconducting piezoelectric effect (SCPE). The SCPE may enable a piezoelectric response without Joule heating and provide a probe of exotic superconducting symmetry. In this paper, we propose a formulation of the SCPE and calculate both the MPE and SCPE in the two-dimensional noncentrosymmetric s-wave superconductor under an in-plane magnetic field. We find that the magnitude of the SCPE is comparable to the MPE. It is also clarified that finite total momentum of Cooper pairs in the helical superconducting state plays a crucial role in the SCPE.