Signatures of Floquet Engineering in the proximal Kitaev Quantum Spin Liquid H$_3$LiIr$_2$O$_6$ by tr-RIXS

TL;DR

This study demonstrates the use of time-resolved RIXS to observe Floquet engineering effects on magnetic excitations in a Kitaev quantum spin liquid candidate, highlighting experimental challenges and potential solutions.

Contribution

First experimental application of circularly polarized Floquet engineering in a Kitaev system using tr-RIXS, showing modifications in magnetic excitations during laser illumination.

Findings

Magnetic excitations are modified during laser illumination.

Experimental challenges include penetration length mismatch.

Proposed solutions for observing Floquet-stabilized Kitaev QSL.

Abstract

We present the first circularly polarized Floquet engineering time-resolved Resonant Inelastic X-ray Scattering (tr-RIXS) experiment in H$_3$LiIr$_2$O$_6$, an iridium-based Kitaev system. Our calculations and experimental results are consistent with the modification of the low energy magnetic excitations in H$_3$LiIr$_2$O$_6$ only during illumination by the laser pulse, consistent with the Floquet engineering of the exchange interactions. However, the penetration length mismatch between the X-ray probe and laser pump and the intrinsic complexity of Kitaev magnets prevented us from unequivocally extracting towards which ground H$_3$LiIr$_2$O$_6$ was driven. We outline possible solutions to these challenges for Floquet stabilization and observation of the Kitaev Quantum Spin Liquid limit by RIXS.