Seminars

Surface states in Bernal and rhombohedral graphite

Graphite is a semimetal allowing for unprecedented electrostatic control of its surface states via hBN encapsulation and gating. Graphite with Bernal (ABA) and rhombohedral (ABC) stacking have notably different electronic properties: Bernal graphite is a semimetal with small electron and hole Fermi surfaces and no surface states; Rhombohedral graphite is also a semimetal, but thin films thereof are insulating in the bulk and host 2D metallic surface states.

With self-consistent Hartree calculation we show that surface states do appear at the surface of Bernal graphite upon electrostatic doping [1], these are: (1) compressible surface states that form a 2D metal on the surface, and (2) incompressible surface states that may appear above or below the Fermi level. The results are confirmed experimentally by quantum capacitance spectroscopy.

For surface states in rhombohedral graphite films we calculate the phase diagram, predicting a pattern of gate-induced topological Lifshitz transitions between metallic surface states with different Fermi surface topology. We find a giant anomalous Hall effect growing with the number of layers, that is induced by magnetic field or circularly-polarized light.

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