Bulletin of the American Physical Society
APS March Meeting 2018
Monday–Friday, March 5–9, 2018; Los Angeles, California
Session P14: Topological Materials - Theory and computation
2:30 PM–5:30 PM,
Wednesday, March 7, 2018
LACC Room: 304B
Sponsoring Unit: DMP
Chair: Haizhou Lu, Southern University of Science and Technology, China
Abstract: P14.00010 : Antiferromagnetic Chern insulators in non-centrosymmetric systems
4:42 PM–4:54 PM
(Institute of Theoretical Physics, Chinese Academy of Sciences)
(Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences)
A new class of topological antiferromagnetic (AF) Chern insulators driven by electronic interactions can emerge from two-dimensional systems without inversion symmetry. Despite the absence of a net magnetization,
the AF Chern insulators (AFCI) possess a nonzero Chern number $C$ and exhibit the quantum anomalous Hall effect (QAHE). Their existence is guaranteed by the bifurcation of the boundary line of Weyl points between a quantum spin Hall insulator and a topologically trial phase and the emergence of AF order. As a concrete example, we study the phase structure of the honeycomb lattice Kane-Mele model as a function of the inversion-breaking ionic potential $\Delta$ and the Hubbard interaction $U$.
We find a special point $(\Delta_c,U_c)$ where a line of Weyl points terminates and the band insulator, quantum spin Hall insulator, and an easy $z$-axis $C=1$ AFCI meet. Because of the broken spin-rotation symmetry by spin-orbit coupling, there is a spin-flop transition from the $z$-axis AFCI to the topological trial antiferromagnets with collinear ordered moments in the $xy$-plane.
We propose possible experimental realizations of the AFCI and QAHE in correlated electron materials and cold atom systems.
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