Abstract. 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 Γ-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 E_F 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.

PACS numbers: 72.15.Jf, 71.20.Nr, 79.60.-i

Print publication: Issue 5 (March 2008)
Received 23 October 2007, accepted for publication 14 January 2008
Published 12 February 2008