Superconducting Berry Curvature Dipole

TL;DR

This paper introduces the concept of a superconducting Berry curvature dipole (BCD) in noncentrosymmetric superconductors, revealing its dependence on the superconducting gap phase and structure, and its potential for nonlinear electromagnetic responses.

Contribution

It uncovers a collective many-body phenomenon called superconducting BCD, linking it to nonreciprocal responses and nonlinearities in superconductors, which was not previously understood.

Findings

Superconducting BCD is sensitive to the superconducting gap phase.

Superconducting BCD depends on the noncentrosymmetric pairing structure.

Superconducting BCD induces giant second-order nonlinear electromagnetic responses.

Abstract

Superconductivity and Bloch band Berry curvature responses represent two distinct paradigms of quantum coherent phenomena. The former relies on the collective motion of a many-body state while the latter proceeds from the momentum-space winding of Bloch wavefunctions. Here we reveal a superconducting Berry curvature dipole (BCD) that arises as a collective many-body phenomena in noncentrosymmetric superconductors. Strikingly, we find the superconducting BCD is sensitive to the phase of the superconducting gap and depends on the noncentrosymmetric structure of its pairing. This unusual property enables a BCD proximity effect in hybrid quantum materials that induces nonreciprocity even in a target centrosymmetric metal. We find superconducting BCD naturally produces nonreciprocal electromagnetic responses that includes a giant second-order nonlinearity. This renders noncentrosymmetric superconductors an exciting platform for realizing pronounced nonlinearities and its BCD responses a novel diagnostic of the superconducting gap.