报告题目：Symmetry and topological nature in a two-dimensional topological insulator coupled with a high-Tc superconductor
报告内容：Previously based on a phenomenological model, it was proposed that the higher order topological superconductivity can be realized in a heterostructure with the two-dimensional topological insulator and the high-temperature superconductor. The Majorana bound states naturally emerge at the corners of the system. Here starting from a microscopic model, we restudy this system theoretically. In the momentum space, the four-fold rotational symmetry of the quasiparticle spectra is broken. For a cylinder geometry, the zero energy edge states may appear but they are localized at one boundary. For the finite-size system with open boundaries, the Majorana bound states only emerge at parts of the system corners. These results are significantly different from those obtained based on the phenomenological model. All of the results can be understood well through exploring the pairing order parameter and the anomalous Green's function.