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HL: Fachverband Halbleiterphysik
HL 57: Spintronics/Quantum information: Materials and methods (HL, jointly with TT)
HL 57.11: Talk
Wednesday, March 13, 2013, 17:45–18:00, H2
Enhanced Infrared Magneto-Optical Response of the Nonmagnetic Semiconductor BiTeI Driven by Bulk Rashba Splitting — •L. Demko1, G. A. H. Schober3, V. Kocsis4, M. S. Bahramy5, H. Murakawa5, J. S. Lee2, I. Kezsmarki4, R. Arita2, N. Nagaosa2, and Y. Tokura1 — 1Multiferroics Project, ERATO, JST, c/o Department of Applied Physics, University of Tokyo, Japan — 2Department of Applied Physics, University of Tokyo, Japan — 3Institute for Theoretical Physics, University of Heidelberg, Germany — 4Department of Physics, Budapest University of Technology and Economics and Condensed Matter Research Group of the Hungarian Academy of Sciences, Hungary — 5CMRG and CERG, RIKEN ASI, Japan
We study the magneto-optical (MO) response of the polar semiconducting BiTeI with giant bulk Rashba spin splitting at various carrier densities. Despite being nonmagnetic, the material is found to yield a huge MO activity in the infrared region under moderate magnetic fields (up to 3 T). Our first-principles calculations show that the enhanced MO response of BiTeI comes mainly from the intraband transitions between the Rashba-split bulk conduction bands. These transitions connecting electronic states with opposite spin directions become active due to the presence of strong spin-orbit interaction and give rise to distinct features in the MO spectra with a systematic doping dependence. We predict an even more pronounced enhancement in the low-energy MO response and dc Hall effect near the crossing (Dirac) point of the conduction bands.