Footprints of the Kitaev spin liquid in the Fano lineshapes of the Raman active optical phonons

Fuente: arXiv
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Autori principali: Feng, Kexin, Swarup, Swetlana, Perkins, Natalia B.
Natura: Preprint
Pubblicazione: 2021
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author Feng, Kexin
Swarup, Swetlana
Perkins, Natalia B.
author_facet Feng, Kexin
Swarup, Swetlana
Perkins, Natalia B.
contents We develop a theoretical description of the Raman spectroscopy in the spin-phonon coupled Kitaev system and show that it can provide intriguing observable signatures of fractionalized excitations characteristic of the underlying spin liquid phase. In particular, we obtain the explicit form of the phonon modes and construct the coupling Hamiltonians based on $D_{3d}$ symmetry. We then systematically compute the Raman intensity and show that the spin-phonon coupling renormalizes phonon propagators and generates the salient Fano linshape. We find that the temperature evolution of the Fano lineshape displays two crossovers, and the low temperature crossover shows pronounced magnetic field dependence. We thus identify the observable effect of the Majorana fermions and the $Z_2$ gauge fluxes encoded in the Fano lineshape. Our results explain several phonon Raman scattering experiments in the candidate material $α$-RuCl$_3$.
format Preprint
id arxiv_https___arxiv_org_abs_2108_08878
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Footprints of the Kitaev spin liquid in the Fano lineshapes of the Raman active optical phonons
Feng, Kexin
Swarup, Swetlana
Perkins, Natalia B.
Strongly Correlated Electrons
We develop a theoretical description of the Raman spectroscopy in the spin-phonon coupled Kitaev system and show that it can provide intriguing observable signatures of fractionalized excitations characteristic of the underlying spin liquid phase. In particular, we obtain the explicit form of the phonon modes and construct the coupling Hamiltonians based on $D_{3d}$ symmetry. We then systematically compute the Raman intensity and show that the spin-phonon coupling renormalizes phonon propagators and generates the salient Fano linshape. We find that the temperature evolution of the Fano lineshape displays two crossovers, and the low temperature crossover shows pronounced magnetic field dependence. We thus identify the observable effect of the Majorana fermions and the $Z_2$ gauge fluxes encoded in the Fano lineshape. Our results explain several phonon Raman scattering experiments in the candidate material $α$-RuCl$_3$.
title Footprints of the Kitaev spin liquid in the Fano lineshapes of the Raman active optical phonons
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2108.08878