Detecting monopole charge in Weyl semimetals via quantum interference transport

TL;DR

This paper links the monopole charge parity in Weyl semimetals to quantum interference effects, proposing a method to detect monopole charges through magnetoconductivity measurements.

Contribution

It establishes a theoretical connection between monopole charge parity and quantum interference corrections, providing a new way to detect monopole charges in Weyl semimetals.

Findings

Odd monopole charge leads to weak anti-localization effects.

Even monopole charge results in weak localization effects.

Low-temperature magnetoconductivity scales as ±√B, depending on monopole charge parity.

Abstract

Topological Weyl semimetals can host Weyl nodes with monopole charges in momentum space. How to detect the signature of the monopole charges in quantum transport remains a challenging topic. Here, we reveal the connection between the parity of monopole charge in topological semimetals and the quantum interference corrections to the conductivity. We show that the parity of monopole charge determines the sign of the quantum interference correction, with odd and even parity yielding the weak anti-localization and weak localization effects, respectively. This is attributed to the Berry phase difference between time-reversed trajectories circulating the Fermi sphere that encloses the monopole charges. From standard Feynman diagram calculations, we further show that the weak-field magnetoconductivity at low temperatures is proportional to $+\sqrt{B}$ in double-Weyl semimetals and $-\sqrt{B}$ in Weyl semimetals, respectively, which could be verified experimentally.