Surface spectral function in the superconducting state of a topological insulator

TL;DR

This paper analyzes the surface spectral function of superconducting topological insulators, highlighting how different bulk pairing symmetries influence surface states and revealing exotic spectra such as Andreev bound states.

Contribution

It provides a comparative study of surface spectral functions in superconducting topological insulators using two models and explores the effects of pairing symmetry, especially odd-parity pairing.

Findings

Surface spectral functions depend on bulk pairing symmetry.

Odd-parity pairing leads to exotic surface spectra.

Andreev bound states are connected to topological surface states.

Abstract

We discuss the surface spectral function of superconductors realized from a topological insulator, such as the copper-intercalated Bi$_{2}$Se$_{3}$. These functions are calculated by projecting bulk states to the surface for two different models proposed previously for the topological insulator. Dependence of the surface spectra on the symmetry of the bulk pairing order parameter is discussed with particular emphasis on the odd-parity pairing. Exotic spectra like an Andreev bound state connected to the topological surface states are presented.