Films of rhombohedral graphite as two-dimensional topological semimetals

Slizovskiy, Sergey and McCann, Edward and Koshino, Mikito and Falko, Vladimir (2019) Films of rhombohedral graphite as two-dimensional topological semimetals. Communications Physics, 2: 164. ISSN 2399-3650

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Abstract

Topologically non-trivial states appear in a number of materials ranging from spin-orbit-coupling driven topological insulators to graphene. In multivalley conductors, such as mono- and bilayer graphene, despite a zero total Chern number for the entire Brillouin zone, Berry curvature with different signs concentrated in different valleys can affect the material’s transport characteristics. Here we consider thin films of rhombohedral graphite, which appear to retain truly two-dimensional properties up to tens of layers of thickness and host two-dimensional electron states with a large Berry curvature, accompanied by a giant intrinsic magnetic moment carried by electrons. The size of Berry curvature and magnetization in the vicinity of each valley can be controlled by electrostatic gating leading to a tuneable anomalous Hall effect and a peculiar structure of the two-dimensional Landau level spectrum.