Fizika Nizkikh Temperatur: Volume 47, Number 9 (September 2021), p. 851-861 ( to contents , go back )
Magnetoelastic effects in the hyperhoneycomb Kitaev spin liquid
Department of Physics, National Research University Higher School of Economics, Moscow, Russia
Lomonosov Moscow State University, Moscow 119991, Russia
Natalia B. Perkins
School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
Received May 6, 2021, published online July 26, 2021
In recent years, several magnetic Mott insulators with strong spin-orbit coupling were suggested to be proximate to the Kitaev quantum spin liquid, whose one of the most exciting features is the fractionalization of spin excitations into itinerant Majorana fermions and static Z2 fluxes. Unfortunately, the ground states of these systems cannot be easily captured by experiment, remaining featureless to conventional local probes. Here we propose to study the signatures of fractionalized excitations by exploiting their coupling to the lattice vibrations, dubbed magnetoelastic coupling, which arises from the fact that the interaction between spins depends on the relative distance between them. We argue that the magnetoelastic coupling can lead to the distinct modification of the phonon dynamics, which can be observed by measuring renormalized phonon spectrum, the sound attenuation and the phonon Hall viscosity. This makes the phonon dynamics a promising tool for the characterization and identification of quantum spin liquid phases. In this work, we focus on the magnetoelastic effects in the three-dimensional Kitaev model realized on the hyperhoneycomb lattice. The hyperhoneycomb Kitaev spin liquid is particularly interesting since the strong Kitaev interaction was observed in the Kitaev magnet β-Li2IrO3, for which the spin-orbit entangled Jeff = 1/2 moments of iridium ions form precisely the hyperhoneycomb lattice.
Key words: phonon dynamics, magnetoelastic coupling, quantum spin liquid.