Universal magnetotunnel conductance at a Weyl semimetal-layered Chern insulator junction

TL;DR

This paper demonstrates that the magneto conductance at a Weyl semimetal-layered Chern insulator junction saturates to a universal value due to topological charge pumping, independent of microscopic details.

Contribution

It reveals a universal saturation of magneto conductance driven by topological charge pumping in Weyl semimetal and Chern insulator junctions.

Findings

Conductance increases linearly with magnetic field at low fields.

Saturates to a universal value beyond a critical magnetic field.

Universality is linked to topological charge pumping, not magnetic breakdown.

Abstract

We investigate electronic transport across a junction between a Weyl semimetal (WSM) and a layered Chern insulator (LCI) in the presence of a magnetic field perpendicular to the interface. The topological mismatch between the gapless Weyl semimetal and the momentum-resolved chiral edge modes of the layered Chern insulator leads to interface Fermi-arc states with a qualitatively distinct connectivity: unlike WSM-WSM junctions, the interface Fermi arcs are forced to reconnect through the Brillouin-zone boundary rather than terminating at the projections of the Weyl nodes. We analyze the spectrum and compute the magneto tunnel conductance mediated by the interface-localized states. We find that the conductance increases linearly with magnetic field at low fields and saturates beyond a critical field to a constant value that is independent of microscopic details such as interface coupling, arc geometry, and lattice-scale parameters. This universal saturation reflects a transport mechanism governed by the topological charge pumping associated with the Chern layers, rather than magnetic breakdown between Fermi arcs. We further show that, under specific conditions, a junction between two distinct Weyl semimetals can exhibit a similar saturation behavior, thereby clarifying the topological origin of the observed universality.