Motivated by the recent experimental observation of a Mott insulating state for the layered iridate Na2IrO3, we discuss possible ordering states of the effective iridium moments in the presence of strong spin-orbit coupling and a magnetic field. For a field pointing in the ⟨111⟩ direction—perpendicular to the hexagonal lattice formed by the iridium moments—we find that a combination of Heisenberg and Kitaev exchange interactions gives rise to a rich phase diagram with both symmetry breaking magnetically ordered phases as well as a topologically ordered phase that is stable over a small range of coupling parameters. Our numerical simulations further indicate two exotic critical points at the boundaries between these ordered phases. Finally, we further study the stability of the topological phase against some other perturbations.
Education and Scientific Employment
1). 2000.9 – 2004.6 B.S., Department of Physics, Zhejiang University
2). 2004.9 – 2009.7 Ph.D., Center for Advanced Study, Tsinghua University, Beijing
Supervisor: Zheng-Yu Weng
3). 2009.7 – Present Postdoctoral Fellow, Microsoft Research, Station Q, Universityof California, Santa Barbara