Magnetic Breakdown and Chiral Magnetic Effect at Weyl-Semimetal Tunnel Junctions

TL;DR

This paper studies magnetotransport phenomena at Weyl-semimetal interfaces, revealing universal conductance behavior and magnetic breakdown effects due to Fermi arc connectivity differences.

Contribution

It uncovers the effects of homochiral and heterochiral Fermi arc connectivities on magnetotransport and introduces the concept of magnetic breakdown at Weyl-semimetal interfaces.

Findings

Universal longitudinal magnetoconductance of e^2/h per flux quantum

Magnetic breakdown enables transition from homochiral to heterochiral connectivity

Conductance saturation occurs above the breakdown field

Abstract

We investigate magnetotransport across an interface between two Weyl semimetals whose Weyl nodes project onto different interface momenta. Such an interface generically hosts Fermi arcs that connect Weyl nodes of identical chirality in different Weyl semimetals (homochiral connectivity) -- in contrast to surface Fermi arcs that connect opposite-chirality Weyl nodes within the same Weyl semimetal (heterochiral connectivity). We show that electron transport along the arcs with homochiral connectivity, in the presence of a longitudinal magnetic field, leads to a universal longitudinal magnetoconductance of $e^2/h$ per magnetic flux quantum. Furthermore, a weak tunnel coupling can result in a close encounter of two homochiral-connectivity Fermi arcs, enabling magnetic breakdown. Above the breakdown field the interface Fermi arc connectivity is effectively heterochiral, leading to a saturation of the conductance.