Supercurrent rectification with time-reversal symmetry broken multiband superconductors

TL;DR

This paper explores how multiband superconductors with broken time-reversal symmetry can produce nonreciprocal supercurrents, revealing complex patterns and dependencies that could help identify such superconducting states.

Contribution

It demonstrates the mechanisms of supercurrent rectification in multiband superconductors with broken time-reversal symmetry, including phase frustration and interband scattering effects.

Findings

Nonreciprocal supercurrent depends on interband phase mismatch and scattering.

Hexagonal nodal line pattern emerges in three-band superconductors.

Supercurrent rectification exhibits three-fold structures sensitive to tunneling amplitudes.

Abstract

We consider nonreciprocal supercurrent effects in Josephson junctions based on multiband superconductors with a pairing structure that can break time-reversal symmetry. We demonstrate that a nonreciprocal supercurrent can be generally achieved by the cooperation of interband superconducting phase mismatch and interband scattering as well as by multiband phase frustration. The effect of interband impurity scattering indicates that the amplitude and sign of the nonreciprocal supercurrent are sensitive to the interband phase relation. For the case of a three-band superconductor, due to phase frustration, we show that the profile of the supercurrent rectification is marked by a hexagonal pattern of nodal lines with vanishing amplitude. Remarkably, around the nodal lines, the supercurrent rectification amplitude exhibits three-fold structures with an alternating sign. We show that the hexagonal pattern and the three-fold structure in the interband phase space turn out to be dependent on the tunneling amplitude of each band. These findings provide hallmarks of the supercurrent rectification which can be potentially employed to unveil the occurrence of spin-singlet multiband superconductivity with time-reversal symmetry breaking.