Volume 81, Number 5, March 2008
Article Number 57006
Number of page(s) 5
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
Published online 12 February 2008
EPL, 81 (2008) 57006
DOI: 10.1209/0295-5075/81/57006

Spin-orbit interaction effect in the electronic structure of Bi2Te3 observed by angle-resolved photoemission spectroscopy

H.-J. Noh1, 2, H. Koh2, S.-J. Oh2, J.-H. Park3, H.-D. Kim4, J. D. Rameau5, 6, T. Valla5, T. E. Kidd5, P. D. Johnson5, Y. Hu5 and Q. Li5

1  Department of Physics, Chonnam National University - Gwangju 500-757, Korea
2  School of Physics & Center for Strongly Correlated Materials Research, Seoul National University Seoul 151-742, Korea
3  Department of Physics, Pohang University of Science and Technology - Pohang 790-784, Korea
4  Pohang Accelerator Laboratory, Pohang University of Science and Technology - Pohang 790-784, Korea
5  Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory Upton, NY 11973, USA
6  Department of Physics & Astronomy, Stony Brook University - Stony Brook, NY 11974, USA

received 23 October 2007; accepted in final form 14 January 2008; published March 2008
published online 12 February 2008

The electronic structure of p-type doped Bi2Te3 is studied by angle-resolved photoemission spectroscopy (ARPES) to experimentally confirm the mechanism responsible for the high thermoelectric figure of merit. Our ARPES study shows that the band edges are located off the $\Gamma $-Z line in the Brillouin zone, which provides direct observation that the spin-orbit interaction is a key factor to understand the electronic structure and the corresponding thermoelectric properties of Bi2Te3. A successive time-dependent ARPES measurement also reveals that the electron-like bands crossing EF near the $\underline{\Gamma} $-point are formed in an hour after cleaving the crystals. We interpret these as surface states induced by surface band bending, possibly due to quintuple inter-layer distance change of Bi2Te3.

72.15.Jf - Thermoelectric and thermomagnetic effects.
71.20.Nr - Semiconductor compounds.
79.60.-i - Photoemission and photoelectron spectra.

© EPLA 2008