Magnetic Field Induced Spin Liquids in S=1 Kitaev Honeycomb Model

Abstract

We investigate the ground state properties of the spin S=1 Kitaev honeycomb model under a magnetic field based on the density matrix renormalization group (DMRG) calculation. With the time reversal symmetry breaking due to the magnetic field, a gapped Kitaev spin liquid is identified for both ferromagnetic (FM) and antiferromagnetic (AFM) Kitaev couplings. The topological nature of such Kitaev spin liquid is manifested by the nearly quantized Wilson loop, degeneracy in the entanglement spectra and existence of edge modes. While the FM Kitaev spin liquid is destroyed by a weaker magnetic field $H_*^\text{FM}$, the AFM one demonstrates a robustness up to an order of magnitude larger critical field $H_*^\text{AFM}$. Moreover, an intermediate nonmagnetic phase appears only for the AFM case at larger fields, $H_*^\text{AFM} < H < H_{**}^\text{AFM}$, before the transition to a high-field polarized paramagnet. The stability of the Kitaev spin liquid against the Heisenberg interactions is also examined. Our findings may further inspire the investigation of recently proposed S=1 Kitaev materials.