Majorana Fermions and Exotic Surface Andreev Bound States in Topological Superconductors: Application to CuxBi2Se3

TL;DR

This paper investigates the surface states of the topological superconductor CuxBi2Se3, revealing Majorana fermions and novel Andreev bound states that align with experimental observations and suggest new experimental signatures.

Contribution

It analytically and numerically characterizes Majorana fermions and new surface Andreev bound states in CuxBi2Se3, advancing understanding of topological superconductors.

Findings

Majorana fermions appear at k=0 and evolve into gapless surface states

Surface Andreev bound states match recent tunneling spectroscopy data

Predictions made for low-temperature tunneling and photoemission experiments

Abstract

The recently discovered superconductor CuxBi2Se3 is a candidate for three-dimensional time- reversal-invariant topological superconductors, which are predicted to have robust surface Andreev bound states hosting massless Majorana fermions. In this work, we analytically and numerically find the linearly dispersing Majorana fermions at k = 0, which smoothly evolve into a new branch of gapless surface Andreev bound states near the Fermi momentum. The latter is a new type of Andreev bound states resulting from both the nontrivial band structure and the odd-parity pairing symmetry. The tunneling spectra of these surface Andreev bound states agree well with a recent point-contact spectroscopy experiment[1] and yield additional predictions for low temperature tunneling and photoemission experiments.