Dr. Joji Nasu (Tokyo Institute of Technology)
"Finite temperature phase transition to a quantum spin liquid in a 3D Kitaev model"
The Kitaev model has recently attracted considerable attention due to the spin-liquid ground states. In the present study, we investigate the thermodynamic properties of a three-dimensional generalization of the Kitaev model defined on a hyperhoneycomb lattice, which was introduced in Ref. [1]. We analyze this model in the limit where one of the inequivalent bonds is stronger than the others by using a Monte Carlo simulation [2]. As a result, we find a phase transition at a finite temperature between the gapped quantum spin liquid and paramagnet. This phase transition is of second order and belongs to the 3D Ising universality class. We provide a topological characterization of the phase transition in terms of a flux density and discuss the magnetic properties in the vicinity of the phase transition.
[1] S. Mandal and N. Surendran, Phys. Rev. B 79, 024426 (2009).
[2] J. Nasu et al., Phys. Rev. B 89,115125 (2014).