Topological Semimetal Thin Films Speaker Name: Professor Susanne Stemmer
Speaker Institution : University of California, Santa Barbara
Abstract : Thin films of topological semimetals offer new opportunities to control and manipulate unique electronic states and a wealth of associated phenomena, for example, via electric field effect, strain, or symmetry breaking. In this presentation, we will discuss recent progress in heterostructures of a prototype three-dimensional Dirac semimetal, cadmium arsenide (Cd3As2), which are grown by molecular beam epitaxy. We show that high-mobility, epitaxial Cd3As2 films can be grown in different crystallographic orientations and that confinement and strain can be used to manipulate their topological states. We discuss their transport properties, such as the nature of the quantum Hall effect that originates from the surface Dirac states. We also discuss potential applications of these films as channel materials in field effect devices for high-frequency applications. For example, calculations based on our experimental measurements of the materials parameters show that ultra-scaled field effect devices with Cd3As2 channels promise cut-off frequencies above 1.5 THz and unique properties, such as linear behavior.