PhysRevResearch.2.033217.pdf (4.07 MB)
Download file

Quantum-classical crossover in the spin-1/2 Heisenberg-Kitaev kagome magnet

Download (4.07 MB)
journal contribution
posted on 11.08.2020, 08:26 by Yang Yang, Natalia Perkins, Fulya Koç, Chi-Huei Lin, Ioannis RousochatzakisIoannis Rousochatzakis
The spin-1/2 Heisenberg kagome antiferromagnet is one of the paradigmatic playgrounds for frustrated quantum magnetism, with an extensive number of competing resonating valence bond (RVB) states emerging at low energies, including gapped and gapless spin liquids and valence bond crystals. Here we revisit the crossover from this quantum RVB phase to a semiclassical regime brought about by anisotropic Kitaev interactions, and focus on the precise mechanisms underpinning this crossover. To this end, we introduce a simple parametrization of the classical ground states (GSs) in terms of emergent Ising-like variables, and use this parametrization: (i) to construct an effective low-energy description of the order-by-disorder mechanism operating in a large part of the phase diagram and (ii) to contrast, side by side, exact diagonalization data obtained from the full basis with that obtained from the restricted (orthonormalized) basis of classical GSs. The results reveal that fluctuation corrections from states outside the restricted basis are strongly quenched inside the semiclassical regime (due to the large anisotropy spin gaps), and that the RVB phase survives up to a relatively large value of Kitaev anisotropy K. We further find that the pure Kitaev model admits a subextensive number of one-dimensional symmetries, which explains naturally the absence of classical and quantum order by disorder reported previously.

Funding

U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award No. DE-SC0018056

History

School

  • Science

Department

  • Physics

Published in

Physical Review Research

Volume

2

Pages

033217

Publisher

American Physical Society

Version

VoR (Version of Record)

Publisher statement

This is an Open Access Article. It is published by American Physical Society under the Creative Commons Attribution 4.0 Unported Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/

Acceptance date

06/07/2020

Publication date

2020-08-07

Copyright date

2020

eISSN

2643-1564

Language

en

Depositor

Dr Ioannis Rousochatzakis . Deposit date: 7 August 2020

Article number

033217

Usage metrics

Categories

Licence

Exports