Signatures of a Majorana-Fermi surface in the Kitaev magnet Ag$_3$LiIr$_2$O$_6$

TL;DR

This paper identifies thermodynamic signatures of itinerant Majorana fermions in the Kitaev magnet Ag$_3$LiIr$_2$O$_6$, providing evidence for a Fermi liquid-like state and suggesting new experimental detection methods.

Contribution

It introduces a Landau-Majorana liquid theory that matches experimental features of the Kitaev spin liquid candidate Ag$_3$LiIr$_2$O$_6$, revealing a Fermi liquid-like ground state.

Findings

Qualitative agreement between Landau-Majorana theory and experiments

Identification of thermodynamic signatures of Majorana fermions

Evidence for a Fermi liquid-like ground state in a honeycomb iridate

Abstract

Detecting Majorana fermions in experimental realizations of the Kitaev honeycomb model is often complicated by non-trivial interactions inherent to potential spin liquid candidates. In this work, we identify several distinct thermodynamic signatures of massive, itinerant Majorana fermions within the well-established analytical paradigm of Landau-Fermi liquid theory. We find a qualitative and quantitative agreement between the salient features of our Landau-Majorana liquid theory and the Kitaev spin liquid candidate Ag$_3$LiIr$_2$O$_6$. Our study presents strong evidence for a Fermi liquid-like ground state in the fundamental excitations of a honeycomb iridate, and opens new experimental avenues to detect itinerant Majorana fermions in condensed matter systems.