Berlin 2012 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 53: Transport: Topological Insulators 3 (jointly with TT, MA)
HL 53.5: Talk
Wednesday, March 28, 2012, 10:30–10:45, BH 334
Interaction and disorder effects in 3D topological insulator thin films — •Elio Koenig1, Pavel Ostrovsky2, Ivan Protopopov2, Igor Gornyi2, and Alexander Mirlin1,2 — 1Institut für Theorie der Kondensierten Materie Karlsruher Institut für Technologie Wolfgang-Gaede-Str. 1 D-76131 Karlsruhe — 2Institut für Nanotechnologie Hermann-von-Helmholtz-Platz 1 76344 Eggenstein-Leopoldshafen
It has been recently predicted that Coulomb interaction drives a surface of a 3D topological insulator into a critical state. We employ the sigma-model formalism to investigate the effect of electron-electron interaction on the transport by surface states in topological insulator thin films. We take into account the interaction of electrons on different surfaces and also the top-bottom asymmetry of the film (different densities of states and strength of disorder on top/bottom surface). This asymmetry is naturally present in experiments where the electronic densities on the surfaces are controlled independently by means of electrostatic gates. The lack of symmetry between top and bottom surfaces is shown to have strong effect on the film conductivity. The interplay of weak antilocalization, Coulomb interaction within and between surfaces and topological protection leads to a rich flow diagram representing the low temperature behavior of the system. The connection with recent experiments on Bi2Se3 films is discussed.