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arXiv · 2104.08195

Equilibrium current in a Weyl-semimetal - superconductor heterostructure

Kevin A. Madsen·Piet W. Brouwer·Maxim Breitkreiz
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Abstract

A heterostructure consisting of a magnetic Weyl semimetal and a conventional superconductor exhibits an equilibrium current parallel to the superconductor interface and perpendicular to the magnetization. Analyzing a minimal model, which as a function of parameters may be in a trivial magnetic insulator phase, a Weyl semimetal phase, or a three-dimensional weak Chern insulator phase, we find that the equilibrium current is sensitive to the presence of surface states, such as the topological Fermi-arc states of the Weyl semimetal or the chiral surface states of the weak Chern insulator. While there is a nonzero equilibrium current in all three phases, the appearance of the surface states in the topological regime leads to a reversal of the direction of the current, compared to the current direction for the trivial magnetic insulator phase. We discuss the interpretation of the surface-state contribution to the equilibrium current as a real-space realization of the superconductivity-enabled equilibrium chiral magnetic effect of a single chirality, predicted to occur in bulk Weyl superconductors.

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Kevin A. Madsen, Piet W. Brouwer, Maxim Breitkreiz. 2021-04-16. Equilibrium current in a Weyl-semimetal - superconductor heterostructure. https://doi.org/10.1103/physrevb.104.035109

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