Ultrathin Sb layers as a new material with two-dimensional (2D) topological insulator properties (2015 - 2018)

Project title Ultrathin Sb layers as a new material with two-dimensional (2D) topological insulator properties
Principal investigator prof. dr hab. Mieczysław Jałochowski
Project ID 2014/13/B/ST5/04442
Sources of funding National Science Centre
Amount of funding 628 840  PLN
Project duration 2015 - 2018

Research project hypothesis and objectives

We propose a complex study of ultrathin antimony films, potentially suited to become topological insulator, a newly discovered materials with unique and intriguing electronic properties. From two indispensable characteristic properties of the topological insulator – existence of energy gap and metallic surface states located within gap with specific symmetry protected by particle number conservation and time reversal symmetry, the antimony possesses only the surface states. Therefore, antimony is not a topological insulator.

The main goal is to learn and to understand mechanisms governing physics leading to opening an energy gap in ultrathin layer of antimony, a material with some topological insulator properties. In particular, we want to study effects of the thin film size quantization, controlled substrate morphology, electronic structure and surface adsorption influence, leading to Sb transition into topological insulator. We presume, that modified in this manner the ultrathin film of Sb should become the two-dimensional (2D) topological insulator.

In semimetal a gap can be opened if the system is sufficiently thin and conditions for creation of quantum well are met. In Sb layer it happens at film thickness of order of a few atomic bilayers. Creation of the gap accompanies the interaction between surface states located at both surface and interface of the film therefore the surface states lose their symmetry. To verify our hypothesis advanced experimental and theoretical studies will be undertaken in order to explain nature of the surface state change due to thin film quantization and surface/interface modification.

 

 

 

We use cookies on our website. Some of them are essential for the operation of the site, while others help us to improve this site and the user experience (tracking cookies). You can decide for yourself whether you want to allow cookies or not. Please note that if you reject them, you may not be able to use all the functionalities of the site.

Ok