United States Department of Energy, Office of Basic Energy Sciences
Three years, $375,385 total
Room-Temperature Topological Insulator Alpha-Sn Thin Films – From Fundamental Physics to Applications
Wu’s project will explore a new topological insulator, alpha-Sn thin films. Topological insulators are materials that behave as insulators on their interiors but are conductive on their surfaces. Conventional topological insulators made from bismuth and samarium-based compounds can host both interior insulation and surface conductivity simultaneously – but only at low temperatures. This has put limitations on the research and applications of those materials.
Recent findings show that alpha-Sn thin films can host this combination of characteristics at room temperature. With this award, Wu aims to answer fundamental questions regarding the surface states in alpha-Sn thin films, namely, spin-momentum locking. Wu will further study the material’s unusual sub-surface states using approaches such as voltage gating.
This project will also examine the effects of topological surface states in alpha-Sn thin films on adjacent magnetic thin films, such as magnetic damping and anisotropy. Wu will explore the possibility of using alpha-Sn thin films to control magnetization dynamics in these films, including domain wall motion and exciting magnetization precession. Topological insulators could one day have a role in improving the efficiency of energy transfer in electronics.