Hybridization Effects of Normal Insulator on Two-Dimensional Topological Insulator

We consider a geometry where a quantum spin Hall insulator and a normal insulator are in contact with each other on the same plane. We show that our numerical results in finite-system approach agree with analytic results of an earlier work in a quantum spin Hall insulator. We discuss the effects of properties of normal insulators on the probability density of edge states at the interface. The edge-state width is computed by varying the interface hopping and the staggered lattice potential. We also attempt to explain the energy dispersions of edge states by constructing effective Hamiltonian and discuss its validity.