Perturbing the Kitaev quantum spin liquid

• Grant number: 23/15537-1
• Support Opportunities: Scholarships in Brazil - Master
• Start date: April 01, 2024
• End date: July 31, 2025
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Eric de Castro e Andrade
• Grantee: Victor Van Driel
• Host Institution: Instituto de Física (IF). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 21/06629-4 - Electronic correlations in quantum materials: inhomogeneities and frustration, AP.JP2
• Associated scholarship(s): 24/13804-5 - Dynamical spin response of inhomogeneous Kitaev materials, BE.EP.MS

Abstract

The Kitaev model is a fascinating example of an exactly solvable model displaying a spin-liquid ground state in two dimensions. However, deviations from the original Kitaev model are expected to appear in real materials that could realize the Kitaev quantum spin liquid (KQSL). In its original version, this model describes a spin liquid of free Majorana fermions hopping in a static Z2 fluxbackground. We want to investigate the fate and properties of theKQSL taking into account the effect of extra exchange terms, which are relevant to understanding its realization in real materials. As a minimal setup, we consider stacked bilayer versions of the Kitaev model. Increasing the ratio between the interlayer Heisenberg coupling J and the intralayer Kitaev coupling K destroys the topological spin liquid in favor of a paramagnetic dimer phase. We plan to study the phase diagram of the model as a function of J/K and to understand the key features in the physical observables, such as the dynamical spin structure factor and the thermal Hall conductivity.