Quantum Spin Liquid phases in Kitaev Materials

Abstract: We develop a gauge-invariant renormalized mean-field theory (RMFT) method, to reliably find the quantum spin liquid (QSL) states and their field response in realistic Kitaev materials. Remarkably, while our RMFT reproduces previous results based on more complicated numerical methods, it also predicts several new stable QSL states. In particular, since Kitaev spin liquid(KSL) is no longer a saddle point solution, a new exotic 2-cone state distinct from the KSL, is found to describe the experimental observations well, and hence the candidate state be realized in the Kitaev material, {\alpha}-RuCl3. We further explore the mechanism for the suppression of the observed thermal Hall conductivity at low temperatures within the fermionic framework, and show the theoretical polarangle dependence of fermionic gap that can distinguish the found 2-cone state from the KSL state in further experiment.