Unconventional Hall Effect in Gapless Superconductors: Transverse Supercurrent Converted from Normal Current

TL;DR

This paper predicts a novel superconducting Hall effect in gapless superconductors, where a normal current is converted into a transverse supercurrent due to quasiparticle Berry curvature, supported by theoretical models.

Contribution

It introduces the superconducting Hall effect in gapless superconductors and explains its origin as quasiparticle Berry curvature, supported by thermodynamic and quantum transport analyses.

Findings

Existence of superconducting Hall effect in gapless superconductors

Conversion of normal current into dissipationless supercurrent

Intrinsic origin linked to quasiparticle Berry curvature

Abstract

A normal metallic system proximitized by a superconductor can exhibit a gapless superconducting state characterized by segmented Fermi surfaces, as confirmed experimentally. In such a state, quasiparticle states remain gapless along one direction, while a superconducting gap opens in the perpendicular direction. This anisotropy enables a novel Hall effect in gapless superconductors, termed the superconducting Hall effect (ScHE), where a longitudinal normal current carried by quasiparticles is converted into a dissipationless transverse supercurrent. Employing both the thermodynamic approach for bulk systems and quantum transport theory for a four-probe setup, we demonstrate the existence of this effect and reveal its intrinsic origin as the quasiparticle Berry curvature. The predicted ScHE can be experimentally verified via the standard angular-dependent Hall measurements performed on gapless superconductors.