Flux crystals, Majorana metals, and flat bands in exactly solvable spin-orbital liquids

Research output: Contribution to journalResearch articleContributedpeer-review

Abstract

Spin-orbital liquids are quantum disordered states in systems with entangled spin and orbital degrees of freedom. We study exactly solvable spin-orbital models in two dimensions with selected Heisenberg-, Kitaev-, and Γ-type interactions, as well as external magnetic fields. These models realize a variety of spin-orbital-liquid phases featuring dispersing Majorana fermions with Fermi surfaces, nodal Dirac or quadratic band touching points, or full gaps. In particular, we show that Zeeman magnetic fields can stabilize nontrivial flux patterns and induce metamagnetic transitions between states with different topological character. Solvable nearest-neighbor biquadratic spin-orbital perturbations can be tuned to stabilize zero-energy flat bands. We discuss in detail the examples of SO(2)- and SO(3)-symmetric spin-orbital models on the square and honeycomb lattices, and use group-theoretical arguments to generalize to SO(ν)-symmetric models with arbitrary integer ν>1. These results extend the list of exactly solvable models with spin-orbital-liquid ground states and highlight the intriguing general features of such exotic phases. Our models are thus excellent starting points for more realistic modelling of candidate materials.

Details

Original languageEnglish
Article number075144
Pages (from-to)075144-075144
Number of pages1
JournalPhysical review. B
Volume103
Issue number7
Publication statusPublished - 24 Feb 2021
Peer-reviewedYes

External IDs

Scopus 85101907481
researchoutputwizard legacy.publication#87715

Keywords

Keywords

  • spin-orbital models, topological phases