Electronic structure of Bi₂Te₃ studied by angle-resolved photoemission

We report a detailed study of the electronic structure of Bi₂Te₃, to our knowledge the best room temperature thermoelectric material known to date, using angle-resolved photoemission. Dispersions of the valence bands were determined. A sixfold k-space degeneracy in the valence-band maximum is found. The quasi-two-dimensional nature of the electronic structure was demonstrated by the weakly dispersive bands along the Γ-Z direction. Experimental results are compared with theoretical band-structure calculations and with de Haas-van Alphen and Shubnikov-de Haas experiments.