Experimental determination of the valence band of Bi$_2$Se$_3$*

P-type Bi$_2$Se$_3$ is predicted theoretically to have good thermoelectric properties[1], because its valence band has a high calculated density of states (DOS). In this presentation, p-type Bi$_2$Se$_3$ samples are prepared both as single crystals and as polycrystals. Shubnikov - de Haas (SdH) measurements are carried out in a rotating stage on single crystals to obtain the Fermi surface cross-sections and the cyclotron effective masses. Thermoelectric transport measurements are done on polycrystals, and used to construct Pisarenko plots of Seebeck coefficient versus hole concentration. The Fermi surface cross-section measurements confirm the theoretically predicted [1] shape of the Fermi surface.Both cyclotron masses and Pisarenko plotsare in good agreement and show that p-type Bi$_2$Se$_3$ has a hole effective mass smaller than the theoretically predicted value. The reason for the discrepancy is not yet understood at this time. Reference: [1] Phys. Rev. X 1, 021005 (2011)