Magnetic breakdown and Klein tunneling in a type-II Weyl semimetal

TL;DR

This paper investigates the unique electronic properties of type-II Weyl semimetals, focusing on magnetic breakdown and Klein tunneling phenomena, and how these effects reveal the topological nature of the Weyl points through quantum oscillations.

Contribution

It identifies signatures of Weyl points in magnetic quantum oscillations and links magnetic breakdown to Klein tunneling, providing new insights into the topological features of type-II Weyl semimetals.

Findings

Signatures of Weyl points in quantum oscillations.

Magnetic breakdown occurs at a characteristic field vanishing near the Weyl point.

Distinct magnetic field dependence distinguishes different Weyl cone configurations.

Abstract

The band structure of a type-II Weyl semimetal has pairs of electron and hole pockets that coexist over a range of energies and touch at a topologically protected conical point. We identify signatures of this Weyl point in the magnetic quantum oscillations of the density of states, observable in thermodynamic properties. Tunneling between the electron and hole pockets in a magnetic field is the momentum space counterpart of Klein tunneling at a p-n junction in real space. This magnetic breakdown happens at a characteristic field that vanishes when the Fermi level approaches the Weyl point. Topologically distinct, connected or disconnected, pairs of type-II Weyl cones can be distinguished by the qualitatively different dependence of the quantum oscillations on the direction of the magnetic field.