Signatures of spinon dynamics and phase structure of dipolar-octupolar quantum spin ices in two-dimensional coherent spectroscopy

TL;DR

This paper demonstrates that two-dimensional coherent spectroscopy can detect fractionalized spinon dynamics and phase transitions in dipolar-octupolar quantum spin ices, revealing temperature-dependent signatures of quantum spin liquid states.

Contribution

It introduces the use of 2DCS to identify spinon fractionalization and phase distinctions in dipolar-octupolar quantum spin ices, a novel application in this context.

Findings

2DCS reveals clear signatures of spinon dynamics.

Temperature influences the sharpness of the 2DCS response.

Lower temperatures distinguish zero-flux and π-flux quantum spin ice states.

Abstract

We study how sharp signatures of fractionalization emerge in nonlinear spectroscopy experiments on spin liquids with separated energy scales. Our model is that of dipolar-octupolar rare earth pyrochlore materials, prime candidates for realising quantum spin ice. This family of three dimensional quantum spin liquids exhibits fractionalization of spin degrees of freedom into spinons charged under an emergent $U(1)$ gauge field. We show that the technique of two dimensional coherent spectroscopy (2DCS) can identify clear signatures of fractionalised spinon dynamics in dipolar-octupolar quantum spin ices. However, at intermediate temperatures, spinon dynamics are heavily constrained in the presence of an incoherent spin background, leading to a broad 2DCS response. At lower temperatures, a sharp signal emerges as the system enters a coherent spin liquid state. This lower temperature signal can in turn distinguish between zero-flux and $\pi$-flux forms of quantum spin ice.