Hae-Young Kee, University of Toronto

"Kitaev Materials and Perspective"

Abstract: Fascinating features of two-dimensional van der Waals magnetic materials have attracted much attention from theoretical and experimental researchers. Recently spin models for two-dimensional Mott insulators beyond the standard Heisenberg interaction have been developed. It was proposed that alpha-RuCl3 is a Kitaev candidate material described by “bond-dependent” spin interactions; the Kitaev model on honeycomb lattice is a rare example of exactly solvable model, which exhibits non-Abelian anyons under a magnetic field. I will first review a microscopic mechanism for the bond-dependent spin interactions starting from spin, orbitals, and their couplings in Mott insulators. There are two types of bond-dependent interactions named Kitaev and Gamma. A minimal Kitaev-Gamma model has been investigated by various numerical techniques under a magnetic field, but definite conclusions about field-induced spin liquids remain elusive. The phase diagram of the Kitaev-Gamma model on the two-leg ladder in the presence of a magnetic field will be presented. Its connection to possible spin liquids in the two-dimensional limit will be also discussed.