Scanning tunneling spectroscopy of Majorana zero modes in a Kitaev spin liquid

TL;DR

This paper investigates the spectroscopic signatures of Majorana zero modes in Kitaev spin liquids using scanning tunneling spectroscopy, revealing conductance features related to vortex configurations and topological states.

Contribution

It provides an exact computation of tunneling conductance signatures of MZMs in Kitaev spin liquids, including vortex detection and differentiation from topological magnon states.

Findings

Conductance exhibits staircase voltage dependence near vortices.

Vortex locations can be identified by scanning the probe tip.

Topological magnon states produce distinct spectroscopic signatures.

Abstract

We describe scanning tunneling spectroscopic signatures of Majorana zero modes (MZMs) in Kitaev spin liquids. The tunnel conductance is determined by the dynamical spin correlations of the spin liquid, which we compute exactly, and by spin-anisotropic cotunneling form factors. Near a $\mathbb{Z}_2$ vortex, the tunnel conductance has a staircase voltage dependence, where conductance steps arise from MZMs and (at higher voltages) from additional vortex configurations. By scanning the probe tip position, one can detect the vortex locations. Our analysis suggests that topological magnon bound states near defects or magnetic impurities generate spectroscopic signatures that are qualitatively different from those of MZMs.