New insights into Kitaev models and materials from few- and many-anyon problems

• Applicant: Professor Dr. Inti Sodemann Villadiego
• Subject Area: Theoretical Condensed Matter Physics
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 542614019

The Kitaev honeycomb model is an exactly solvable Hamiltonian of spins featuring a fascinating ground state with emergent Majorana fermions and non-abelian anyonic particles. However, while materials such as alpha-RuCl3 are described by a model close to the Kitaev Hamiltonian they are also subjected to sizable perturbations that destroy the exact solvability and place them in a different ground state. Our research aims to determine the impact of these perturbations on the Kitaev model by investigating how such perturbations change the dispersions and the symmetry representations of the anyon quasi-particles and their bound states in the Kitaev spin liquid. By systematically and quantitively analyzing how anyons and their bound states are driven to critical points and regimes where they become gapless, we will uncover the nature of the phases that are associated with their proliferation and which surround the ideal Kitaev spin liquid. Our study will shed light on the ultimate nature of the mysterious states observed in alpha-RuCl3, such as those revealed by the oscillations of thermal conductivity that appeared by applying in-plane magnetic fields. We will also develop an avenue of research of Kitaev multilayer models that investigates the nature of states realized in such multilayer extensions of the Kitaev model, and determine the impact of interlayer couplings on the appearance of exotic and conventional states in multilayer Kitaev systems.

• DFG Programme: Research Grants