Patterned Graphite Gate Devices: Towards a New Platform for Studying Topological Edge States in Graphene Systems

Abstract

Quantum materials can host unusual phases of matter, such as superconductivity, by harboring strongly-interacting electrons. Since the discovery of the quantum Hall effect over forty years ago, topological materials have become an area of intense focus in quantum materials research. These materials have non-trivial band structures and support topological edge states with exotic quantum characteristics. These topological edge states, composed of charge carriers, can tell us about the competing energy dynamics and symmetries of the bulk, and can prove useful in a wide variety of applications due to their topologically protected currents. Recently, the interplay between strong electron interactions and band topology has been studied in graphene systems. However, locally probing topological edge states and their electronic properties in these structures is difficult, with one reported study to date. In this thesis, we develop a new platform for studying topological edge modes in graphene with scanning tunneling microscopy and spectroscopy (STM and STS): the patterned graphite gate device. This device allows us to induce two different topological phases within one single contiguous graphene sheet. Moreover, we can tune these two phases independently, and study the interfaces between many different combinations of adjacent topological phases. Future STM and STS studies of patterned graphite gate devices will be able to directly probe topological edge states and determine their electronic properties on the atomic scale. With these capabilities, the interactions between different topological edge modes can also be elucidated.