Three-dimensional Dirac semi-metals such as Na3Bi are a new class of material where electrons behave as relativistic Dirac-like fermions, moving at constant velocity independent of energy, much like massless neutrinos. In the Fuhrer laboratory we utilize a low-temperature (4K) scanning tunnelling microscope (STM) equipped with a molecular beam epitaxy chamber to study Na3Bi grown under ultra-high vacuum conditions. The primary goal of this project will be to investigate the role of quantum confinement on the electronic structure of Na3Bi by growing films of just a few atomic layers (see image below). The confinement of electrons in such thin films gives them a mass, and opens an energy gap between electrons and holes, creating an insulator which may be conventional or topological. We will use scanning tunnelling microscopy and spectroscopy to search for signs of topological insulator behaviour in ultra-thin Na3Bi.
Supervisor: Prof. Michael Fuhrer, Dr Mark Edmonds
See https://www.monash.edu/science/schools/physics/honours/honours-project to apply.