Pressure Induced Quantum Spin Liquids in Extended Kitaev Model

The Kitaev's Honeycomb lattice model has exactly solvable spin liquid ground states and has attracted lots of research interest. However, most Kitaev materials possess both Kitaev and non-Kitaev interactions, resulting in magnetically ordered ground states. A possible way to suppress the magnetic order and to drive the system to quantum spin liquid phases is exerting high pressure, assuming that the bond-dependent interaction strength can be adjusted by the external pressure. We illustrate this possibility by studying a (pressure caused) anisotropic spin model with variational Monte Carlo method. While the anisotropic pure Kitaev model contains only two phases, the presence of non-Kitaev interactions result in a much richer phase diagram and give rise to several gapless spin liquids whose low-energy spinon excitations contain different number of cones. We show that these gapless spin liquids can be distinguished experimentally. Furthermore, a small out-of-plane magnetic field opens a gap to these spin liquids and results in different chiral spin liquids, all of which are belonging to the Kitaev 16-fold classification.