Majorana Landau Level Raman Spectroscopy

TL;DR

This paper proposes using Raman spectroscopy to detect Majorana Landau levels in strained Kitaev quantum spin liquids, providing a potential experimental signature for identifying this elusive phase in materials like $ ext{RuCl}_3$.

Contribution

It introduces a novel method to identify Majorana fermions in quantum spin liquids via Landau level signatures observable through Raman spectroscopy.

Findings

Majorana Landau levels can be induced in strained KQSLs.

Raman spectroscopy can directly detect these Landau levels.

Thin films of $ ext{RuCl}_3$ are suitable for experimental verification.

Abstract

The unambiguous experimental detection of quantum spin liquids and, in particular, of the long-sought Kitaev quantum spin liquid (KQSL) with its Majorana fermion excitations remains an outstanding challenge. One of the major obstacles is the absence of signatures that definitively characterize this phase. Here we propose the Landau levels known to form in the Majorana excitation spectrum of the KQSL when certain strain fields are applied as a direct signature of Majorana fermions with Dirac-like dispersion. In particular, we show that the Majorana Landau level quantization of strained films of the KQSL can be directly probed by Raman spectroscopy. Such experiments are feasible in thin films of $\alpha$-RuCl$_3$, which are a promising place to search for the KQSL.