Topological transition and Majorana zero modes in 2D non-Hermitian chiral superconductor with anisotropy.

We study a non-Hermitian chiral topological superconductor system on two dimensional square lattice, from which we obtained a rich topological phase diagram and established an exact relationship between topological charge flow of exceptional points in generalized Brillouin zone and change of topological properties. Its rich topological phase diagram is the result of competition between anisotropy and non-Hermitian effect. This system belongs to class D according to AZ classification of non-Hermitian systems. Each topological phase can be characterized by a 2D Z number, which indicates the number of chiral edge modes, and two 1D Z 2 numbers, which indicate the existence of zero modes at edge dislocations.