Antiferromagnetic Chern insulators in non-centrosymmetric systems

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.