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