Charge/Spin Supercurrent and the Fulde-Ferrell State Induced by Crystal Deformation in Weyl/Dirac Superconductors

TL;DR

This paper demonstrates that crystal deformation-induced chiral magnetic fields in Weyl/Dirac superconductors can stabilize the Fulde-Ferrell state and generate charge/spin supercurrents parallel to the field, revealing a novel chiral magnetic effect.

Contribution

It provides a microscopic Ginzburg-Landau analysis showing how emergent chiral magnetic fields influence Cooper pairs and induce supercurrents in Weyl/Dirac superconductors, a new phenomenon.

Findings

Chiral magnetic fields stabilize the Fulde-Ferrell state.

Charge/spin supercurrents flow parallel to the chiral magnetic field.

No Meissner or vortex effects due to chiral magnetic fields.

Abstract

It has been predicted that emergent chiral magnetic fields can be generated by crystal deformation in Weyl/Dirac metals and superconductors. The emergent fields give rise to chiral anomaly phenomena as in the case of Weyl semimetals with usual electromagnetic fields. Here, we clarify effects of the chiral magnetic field on Cooper pairs in Weyl/Dirac superconductors on the basis of the Ginzburg-Landau equation microscopically derived from the quasiclassical Eilenberger formalism. It is found that Cooper pairs are affected by the emergent chiral magnetic field in a dramatic way, and the pseudo-Lorentz force due to the chiral magnetic field stabilizes the Fulde-Ferrell state and causes a charge/spin supercurrent which flows parallel to the chiral magnetic field in the case of Weyl/Dirac superconductors. This effect is in analogy with the chiral magnetic effect (CME) of Weyl semimetals. In addition, we elucidate that neither Meissner effect nor vortex state due to chiral magnetic fields occurs.