Challenges of Topological Insulator Research: Bi2Te3Thin Films and Magnetic Heterostructures

Topological insulators (TIs) are of particular interest in the recent solid-state research because of their exceptional features stemming from the conducting, topologically protected surface states. The exotic properties include the occurrence of novel quantum phenomena and make them promising materials for spintronics and quantum computing applications. Theoretical studies have provided a vast amount of valuable predictions and proposals, whose experimental observation and implementation, to date, are often hindered by an insufficient sample quality. The effect of even a relatively low concentration of defects can make the access to purely topological surface states impossible. This points out the need of high-quality bulk-insulating materials with ultra-clean surfaces/interfaces, which requires sophisticated sample/device preparations as well as special precautions during the measurements. Herein, the challenging work on 3D TI thin films with a focus onBi2Te3is reported. It covers the optimization of the molecular beam epitaxy growth process, the in situ characterization of surface states and transport properties, the influence of exposure to ambient gases and of capping layers, as well as the effect of interfacing TI thin film with magnetic materials.

Automated summary

Topological insulators are attracting attention due to their unique conducting, topologically protected surface states and potential applications. Challenges in experimental observations are often caused by sample quality issues, highlighting the need for high-quality bulk-insulating materials. This work focuses on the optimization of thin film growth processes, characterization of surface states, effects of ambient gases and capping layers, and the influence of interfacing with magnetic materials.