Chiral spin liquid near the ferromagnetic Kitaev regime under a magnetic field*

The Kitaev model is a rare example of an exactly solvable model which exhibits a spin liquid ground state, and hosts non-Abelian anyon excitations. Recent research has focused on material realization of Kitaev physics, with α-RuCl₃ emerging as a leading candidate. Compelling evidence for a chiral spin liquid (CSL) is a half-quantized thermal Hall conductivity in α-RuCl₃, a signature of Majorana edge currents. However, it remains a non-trivial task to explain the existence of a CSL in α-RuCl₃ from a microscopic model, due to dominant ferromagnetic (FM) Kitaev interactions. This is because the FM Kitaev phase almost immediately transitions to the polarized phase in an applied field, with no intervening phase. Here we present a microscopic theory describing the existence of a CSL near the FM Kitaev regime under a magnetic field. Further implications related to the quantized thermal Hall conductivity are also discussed.