SurfaceScience21 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 10: Poster Session I: Topological insulators
O 10.4: Poster
Montag, 1. März 2021, 10:30–12:30, P
2D to 3D crossover in topological insulators — •Corentin Morice1, Thilo Kopp2, and Arno Kampf3 — 1Institute for Theoretical Physics Amsterdam and Delta Institute for Theoretical Physics,University of Amsterdam, 1098 XH Amsterdam, The Netherlands — 2Center for Electronic Correlations and Magnetism, Experimental Physics VI,Institute of Physics, University of Augsburg, 86135 Augsburg, Germany — 3Center for Electronic Correlations and Magnetism, Theoretical Physics III,Institute of Physics, University of Augsburg, 86135 Augsburg, Germany
At the heart of the study of topological insulators lies a fundamental dichotomy: topological invariants are defined in infinite systems, but their main footprint, surface states, only exists in finite systems. In systems in the slab geometry, namely infinite in two dimensions and finite in one, the 2D topological invariant was shown to display three different types of behaviours. In the limit of zero Dirac velocity along z, these behaviours extrapolate to the three 3D topological phases: trivial, weak and strong topological insulators. We show analytically that the boundaries of these regions are topological phase transitions of particular significance, and allow one to fully predict the 3D topological invariants from finite-thickness information. Away from this limit, we show that a new phase arises, which displays surface states but no band inversion at any finite thickness, disentangling these two concepts closely linked in 3D.