Terahertz studies and colossal Kerr rotation in the topological insulator Bi$_2$Se$_3$
ORAL
Abstract
We report a study of high quality MBE grown Bi$_2$Se$_3$ topological insulator thin films using time domain terahertz spectroscopy (TDTS). We explicitly demonstrate the 2D character of the response by studying films of different thicknesses. In addition, we take advantage of a unique feature of TDTS that allows to measure the time structure of the THz pulses. In this way we measure the Faraday and Kerr rotation angles in a single experiment. We find an unprecedentedly large value of the Kerr rotation that is due to the cyclotron resonance of the 2D Dirac fermions \footnote{R. Vald\'es Aguilar, \textit{et al}. Arxiv:1105.0237.}. We will also show results on the effect of exposure of the thin films to atmospheric conditions for prolonged periods of time.
*Work supported by The Institute of Quantum Matter under DOE grant DE-FG02-08ER46544 and by the Gordon and Betty Moore Foundation.
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Authors
Rolando Vald\'es Aguilar
Department of Physics \& Astronomy, Johns Hopkins University, Baltimore, MD 21218
A.V. Stier
Department of Physics \& Astronomy, Johns Hopkins University, Baltimore, MD 21218
L. Wu
Department of Physics \& Astronomy, Johns Hopkins University, Baltimore, MD 21218
L.S. Bilbro
Department of Physics \& Astronomy, Johns Hopkins University, Baltimore, MD 21218
W. Liu
Department of Physics \& Astronomy, Johns Hopkins University, Baltimore, MD 21218
N.P. Armitage
Department of Physics \& Astronomy, Johns Hopkins University, Baltimore, MD 21218
N. Bansal
Department of Physics \& Astronomy, Rutgers University, Piscataway, NJ 08854
M. Brahlek
Department of Physics \& Astronomy, Rutgers University, Piscataway, NJ 08854
S. Oh
Department of Physics \& Astronomy, Rutgers University, Piscataway, NJ 08854
D.K. George
Department of Physics, SUNY Buffalo, Buffalo, NY 14260
J. Cerne
Department of Physics, SUNY Buffalo, Buffalo, NY 14260
A.G. Markelz
Department of Physics, SUNY Buffalo, Buffalo, NY 14260
