Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 32: Transport: Topological Insulators - 3D
(Joint session of DS, HL, MA, O and TT organized by TT)
TT 32.3: Vortrag
Dienstag, 8. März 2016, 14:45–15:00, H18
Interaction Correction to the Magneto-Electric Polarizability of Z2 Topological Insulators — •Karin Everschor-Sitte1, Matthias Sitte1, and Allan MacDonald2 — 1Institut für Physik - Johannes Gutenberg-Universität Mainz, Deutschland — 2Department of Physics - University of Texas at Austin, USA
When time-reversal symmetry is weakly broken and interactions are neglected, the surface of a Z2 topological insulator supports a half-quantized Hall conductivity σS = e2/(2h). A surface Hall conductivity in an insulator is equivalent to a bulk magneto-electric polarizability, i.e. to a magnetic field dependent charge polarization. By performing an explicit calculation for the case in which the surface is approximated by a two-dimensional massive Dirac model and time-reversal symmetry is broken by weak ferromagnetism in the bulk, we demonstrate that there is a non-universal interaction correction to σS. Our prediction can be tested by measuring the capacitance of magnetized thin films in which the anomalous quantum Hall effect is absent.