Regensburg 2019 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 5: Topological insulators

HL 5.5: Vortrag

Montag, 1. April 2019, 10:30–10:45, H36

Topological crystalline insulators from stacked graphene layers — •Sanjib Kumar Das1, Binghai Yan2, Jeroen van den Brink1,3, and Ion Cosma Fulga11Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany — 2Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, 7610001, Israel — 3Department of Physics, Technical University Dresden, 01062 Dresden, Germany

In principle the stacking of different two-dimensional (2D) materials allows the construction of 3D systems with entirely new electronic properties. Here we propose to realize topological crystalline insulators (TCI) protected by mirror symmetry in heterostructures consisting of graphene monolayers separated by two-dimensional polar spacers. The polar spacers are arranged such that they can induce an alternating doping and/or spin-orbit coupling in the adjacent graphene sheets. When spin-orbit coupling dominates, the non-trivial phase arises due to the fact that each graphene sheet enters a quantum spin-Hall phase. Instead, when the graphene layers are electron and hole doped in an alternating fashion, a uniform magnetic field leads to the formation of quantum Hall phases with opposite Chern numbers. It thus has the remarkable property that unlike previously proposed and observed TCIs, the non-trivial topology is generated by an external time-reversal breaking perturbation.

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