Evolution of density of states and spin-resolved "checkerboard" pattern associated with Majorana bound state

TL;DR

This paper investigates the evolution of the local density of states and spin-resolved patterns associated with Majorana bound states in topological insulator superconductors, providing theoretical insights aligned with recent experimental observations.

Contribution

It presents a Bogoliubov-de Gennes analysis of Majorana bound states, revealing a spin-resolved checkerboard pattern and spectral evolution consistent with STM/STS experiments.

Findings

Spectral distribution changes from V-shape to Y-shape with MBS emergence.

Identification of a spin-resolved checkerboard pattern in LDOS.

Theoretical support for phase-sensitive detection of MBS using spin-resolved STM/STS.

Abstract

In terms of Bogoliubov-de Gennes approach, we investigate Majorana bound state (MBS) in vortex of proximity-induced superconductivity on the surface of topological insulator. Mapping out the local density of states (LDOS) of quasiparticle excitations as a function of energy and distance from vortex center, it is found that the spectral distribution evolves from "V"-shape to "Y"-shape with emergence of MBS upon variation of chemical potential, consistent with the STM/STS measurement in a very recent experiment [Xu et al., Phys. Rev. Lett. 114, 017001 (2015)] on Bi2Te3 thin layer on the top of NbSe2. Moreover, we demonstrate that there is a "checkerboard" pattern in the relative LDOS between spin up and down channels, which maps out directly the quantum mechanical wave function of MBS. Therefore, spin-resolved STM/STS technique is expected to be able to provide phase sensitive evidence for MBS in vortex core of topological superconductor.