Spinon magnetic resonance of quantum spin liquids

TL;DR

This paper demonstrates that electron spin resonance can directly probe the spinon continuum in quantum spin liquids with strong spin-orbit coupling, revealing broad absorption features and singularities.

Contribution

It introduces a method to analyze spinon resonance in quantum spin liquids using mean-field Hamiltonians and symmetry analysis, providing new insights into their exotic excitations.

Findings

Resonance directly probes spinon continuum

Absorption band is broad with van Hove singularities

Pronounced polarization dependence observed

Abstract

We describe electron spin resonance in a quantum spin liquid with significant spin-orbit coupling. We find that the resonance directly probes spinon continuum which makes it an efficient and informative probe of exotic excitations of the spin liquid. Specifically, we consider spinon resonance of three different spinon mean-field Hamiltonians, obtained with the help of projective symmetry group analysis, which model a putative quantum spin liquid state of the triangular rare-earth antiferromagnet YbMgGaO4. The band of absorption is found to be very broad and exhibit strong van Hove singularities of single spinon spectrum as well as pronounced polarization dependence.