Magnetoinfrared spectroscopic study of thin Bi2Te3 single crystals

Thin Bi2Te3 single crystals laid on Scotch tape are investigated by Fourier transform infrared spectroscopy at 4 K and in a magnetic field up to 35 T. The magnetotransmittance spectra of the Bi2Te3/tape composite are analyzed as a stacked-slab system, and the average thickness of Bi2Te3 is estimated to be 6.4 +/- 1.7 mu m. The optical conductivity of Bi2Te3 at different magnetic fields is then extracted, and we find that the magnetic field modifies the optical conductivity in the following ways: (1) Field-induced transfer of the optical weight from the lower-frequency regime (< 250 cm(-1)) to the higher-frequency regime (> 250 cm(-1)) due to the redistribution of charge carriers across the Fermi surface. (2) Evolving of a Fano-resonance-like spectral feature from an antiresonance to a resonance with increasing magnetic field. Such behavior can be attributed to the electron-phonon interactions between the E-u(1) optical phonon mode and the continuum of electronic transitions. (3) Cyclotron resonance resulting from the intervalence band Landau level transitions, which can be described by the electrodynamics of massive Dirac holes.