Detection of Fermi Arcs in Weyl Semimetals through Surface Negative Refraction

TL;DR

This paper proposes a method to detect Fermi arc surface states in Weyl semimetals using surface negative refraction, observable through non-local transport measurements, providing a clear signature of these exotic states.

Contribution

It introduces a novel detection technique based on negative refraction between surfaces with Fermi arcs, applicable to both inversion and time-reversal symmetric Weyl semimetals.

Findings

Negative refraction causes a return conductance peak.

Conductance oscillations occur in time-reversal symmetric cases.

Method offers a new way to observe Fermi arcs experimentally.

Abstract

One of the main features of Weyl semimetals is the existence of Fermi arc surface states at their surface, which cannot be realized in pure two-dimensional systems in the absence of many-body interactions. Due to the gapless bulk of the semimetal, it is, however, challenging to observe clear signatures from the Fermi arc surface states. Here, we propose to detect such novel surface states via perfect negative refraction that occurs between two adjacent open surfaces with properly orientated Fermi arcs. Specifically, this phenomenon visibly manifests in non-local transport measurement, where the negative refraction generates a return peak in the real-space conductance. This provides a unique signature of the Fermi arc surface states. We discuss the appearance of this peak both in inversion and time-reversal symmetric Weyl semimetals, where the latter exhibits conductance oscillations due to multiple negative refraction scattering events.