Transforming a Surface State of Topological Insulator by a Bi Capping Layer

TL;DR

This paper demonstrates a novel method to engineer topologically protected surface states on a topological insulator by capping it with a bismuth monolayer, resulting in new spin helical states with potential for tailored electronic applications.

Contribution

The study introduces a new approach to modify topological surface states using a Bi monolayer, preserving bulk topology while creating customizable surface channels.

Findings

Original surface state is replaced by three new spin helical states.

New states originate from Bi film and exhibit different dispersion and spin polarization.

The bulk topological nature remains unchanged.

Abstract

We introduce a dinstint approach to engineer a topologically protected surface state of a topological insulator. By covering the surface of a topological insulator, Bi2Te2Se, with a Bi monolayer film, the original surface state is completely removed and three new spin helical surface states, originating from the Bi film, emerge with different dispersion and spin polarization, through a strong electron hybridization. These new states play the role of topological surface states keeping the bulk topological nature intact. This mechanism provides a way to create various different types of topologically protected electron channels on top of a single topological insulator, possibly with tailored properties for various applications.