Faraday Rotation Due to Surface States in the Topological Insulator (Bi1–xSb<subx )2Te3

• Published in: Nano letters Vol. 17; no. 2
• Main Authors: Shao, Yinming, Post, Kirk W., Wu, Jhih-Sheng, Dai, Siyuan, Frenzel, Alex J., Richardella, Anthony R., Lee, Joon Sue, Samarth, Nitin, Fogler, Michael M., Balatsky, Alexander V., Kharzeev, Dmitri E., Basov, D. N.
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 29.12.2016
• Subjects: Bismuth antimony telluride; cyclotron resonance; Faraday rotation; MATERIALS SCIENCE; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; topological insulators; topological surface states
• ISSN: 1530-6984; 1530-6992

For this research, using magneto-infrared spectroscopy, we have explored the charge dynamics of (Bi,Sb)2Te3 thin films on InP substrates. From the magneto-transmission data we extracted three distinct cyclotron resonance (CR) energies that are all apparent in the broad band Faraday rotation (FR) spectra. This comprehensive FR-CR data set has allowed us to isolate the response of the bulk states from the intrinsic surface states associated with both the top and bottom surfaces of the film. Finally, the FR data uncovered that electron- and hole-type Dirac Fermions reside on opposite surfaces of our films, which paves the way for observing many exotic quantum phenomena in topological insulators.