Ozdemir Servet Ozdemir | Akateeminen Kirjakauppa

This thesis presents the first systematic electron transport investigation of rhombohedral graphite (RG) films and thus lies at the interface of graphene physics, vdW heterostructure devices and topological matter. Electron transport investigation into the rhombohedral phase of graphite was limited to a few layers of graphene due to the competing hexagonal phase being more abundant. This work reports that in exfoliated natural graphite films, rhombohedral domains of up to 50 layers can be found. In the low energy limit, these domains behave as an N-layer generalisation of graphene. Moreover, being a potential alternative to twisted bilayer graphene systems, RG films show a spontaneous metal-insulator transition, with characteristic symmetry properties that could be described by mean-field theory where superconductivity is also predicted in these low energy bands. A nodal-line semimetal in the bulk limit, RG thin films are a 3D generalisation of the simplest topological insulator model:the Su-Schrieffer-Heeger chain. Similar to the more usual topological insulators, RG films exhibit parallel conduction of bulk states, which undergo three-dimensional quantum transport that reflects bulk topology.