Finite bulk Josephson currents and chirality blockade removal from inter-orbital pairing in magnetic Weyl semimetals

TL;DR

This paper investigates how inter-orbital pairing in magnetic Weyl semimetals enables finite Josephson currents despite the chirality blockade that suppresses conventional intra-orbital superconducting pairing.

Contribution

It reveals that inter-orbital s-wave and p-wave pairings can propagate into the bulk of WSMs, leading to finite Josephson currents even when intra-orbital pairing is blocked.

Findings

Inter-orbital pairing propagates into the WSM bulk.

Finite Josephson current persists despite chirality blockade.

Both even- and odd-frequency pairing symmetries are involved.

Abstract

Magnetic Weyl semimetals (WSMs) have been presumed to be immune to proximity-induced spin-singlet superconducting pairing due to a chirality blockade of the regular Andreev reflection. In this work we study all possible superconducting pairing induced in a WSM sandwiched between two conventional superconductors in a Josephson junction setup. We confirm that, while conventional intra-orbital $s$-wave pairing is present on the surface of the WSM, it cannot propagate into the bulk due to the chirality blockade. However, inter-orbital $s$-wave pairing, with both even-frequency spin-singlet and odd-frequency mixed-spin triplet symmetry, propagates into the bulk of the WSM, as do several $p$-wave symmetries. To demonstrate the importance of these finite inter-orbital and $p$-wave pair amplitudes in an experimental setup, we calculate the Josephson current and find a finite and even increasing current when the chirality blockade effect for the conventional intra-orbital pairing is enhanced.