Realization of bulk insulating property and carrier manipulation in reversible spin current regime of the ideal topological insulator TlBiSe2

TL;DR

This paper demonstrates the achievement of bulk insulating properties in TlBiSe2 by composition tuning, enabling better exploration of its topological surface states and potential for exotic phenomena and applications.

Contribution

It introduces a method to realize bulk insulating behavior in TlBiSe2 through composition tuning without guest atoms, advancing topological insulator research.

Findings

Bulk insulating property achieved in TlBiSe2

Surface Dirac cone utilized for exotic phenomena

Composition tuning without guest atoms

Abstract

The surfaces of three-dimensional topological insulators (TIs) characterized by a spin-helical Dirac fermion provide a fertile ground for realizing exotic phenomena as well as having potential for wide-ranging applications. To realize most of their special properties, the Dirac point (DP) is required to be located near the Fermi energy with a bulk insulating property while it is hardly achieved in most of the discovered TIs. It has been recently found that TlBiSe2 features an in-gap DP, where upper and lower parts of surface Dirac cone are both utilized. Nevertheless, investigations of the surface transport properties of this material are limited due to the lack of bulk insulating characteristics. Here, we present the first realization of bulk insulating property by tuning the composition of Tl1-xBi1+xSe2-d without introducing guest atoms that can bring the novel properties into the reality. This result promises to shed light on new exotic topological phenomena on the surface.