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arXiv · 1909.09360

Phonon renormalization in the Kitaev quantum spin liquid

Alexandros Metavitsiadis·Wolfram Brenig
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Abstract

We study the self-energy of phonons, magnetoelastically coupled to the two-dimensional Kitaev spin-model on the honeycomb lattice. Fractionalization of magnetic moments into mobile Majorana matter and a static $\mathbb{Z}_{2}$ gauge field lead to a continuum of relaxation processes comprising two channels. Thermal flux excitations, which act as an emergent disorder, strongly affect the phonon renormalization. Above the flux proliferation temperature, the dispersion of a narrow quasiparticle-hole channel is suppressed in favor of broad and only weakly momentum dependent features, covering large spectral ranges. Our analysis is based on complementary calculations in the low-temperature homogeneous gauge and a mean-field treatment of thermal gauge fluctuations, valid at intermediate and high temperatures.

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Alexandros Metavitsiadis, Wolfram Brenig. 2019-09-20. Phonon renormalization in the Kitaev quantum spin liquid. https://doi.org/10.1103/physrevb.101.035103

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