Variational study of the spin-1 Kitaev model

• Grant number: 24/11530-5
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• Start date: January 20, 2025
• End date: July 19, 2025
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Eric de Castro e Andrade
• Grantee: Carlo de Castro Bellinati
• Supervisor: Hong-Hao Tu
• Host Institution: Instituto de Física (IF). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Ludwig Maximilian University of Munich (LMU Munich), Germany
• Associated to the scholarship: 23/06101-5 - Studying spin-liquid phases with projected wave functions, BP.MS

Abstract

Over the last few years, much attention has been devoted to investigating exotic phases of matter in spin-orbit Mott insulators, which are stabilized due to the combination of strong spin-orbit coupling and electronic correlations. A prime example is the Kitaev spin liquid for S=1/2, where the local moments fractionalize into Majorana fermions and static Z2 fluxes. A natural question is whether this exotic phase can be generalized for larger spins, where one expects, on general grounds, quantum fluctuations to decrease and ordered states to be favored. Intriguingly, the spin-S Kitaev model retains the static Z2 flux structure, indicating that the ground state is always a spin liquid. However, because the model for S>1/2 is no longer exactly solvable, the precise nature of this liquid phase is unclear. In this project, we plan to characterize the nature of this liquid phase, its low-energy excitations, and its leading instabilities. To implement this program, we will solve the model via projected wave functions, combining the parton construction with Matrix Product States (MPS). This versatile and successful approach is expected to provide a clear physical picture of the problem.