Record Surface State Mobility and Quantum Hall Effect in Topological Insulator Thin Films via Interface Engineering

TL;DR

This study introduces a novel interface engineering approach using a heterostructure buffer layer to significantly enhance mobility in topological insulator thin films, enabling the first observation of the quantum Hall effect in Bi2Se3.

Contribution

It presents a new buffer layer scheme that improves surface state mobility and allows quantum Hall effect observation in Bi2Se3 thin films.

Findings

Enhanced mobility by an order of magnitude

First observation of quantum Hall effect in Bi2Se3

Successful interface engineering in topological insulators

Abstract

Material defects remain as the main bottleneck to the progress of topological insulators (TIs). In particular, efforts to achieve thin TI samples with dominant surface transport have always led to increased defects and degraded mobilities, thus making it difficult to probe the quantum regime of the topological surface states. Here, by utilizing a novel buffer layer scheme composed of an In2Se3/(Bi0.5In0.5)2Se3 heterostructure, we introduce a quantum generation of Bi2Se3 films with an order of magnitude enhanced mobilities than before. This scheme has led to the first observation of the quantum Hall effect in Bi2Se3.