April 26th, 17:00 CEST: Hae-Young Kee (University of Toronto, Canada)
Kitaev Materials and Perspective
Fascinating features of two-dimensional van der Waals (vdW) magnetic materials have attracted much attention from theoretical and experimental researchers. Recently spin models for vdW 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 to 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 (KG) 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 KG model defined on a two-leg ladder in the presence of magnetic field will be presented. We will then discuss its connection to possible spin liquids in the two-dimensional limit.