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Magnetothermoelectric properties of Bi2Se3

We present a study of entropy transport in Bi2Se3 at low temperatures and high magnetic fields. In the zero-temperature limit, the magnitude of the Seebeck coefficient quantitatively tracks the Fermi temperature of the 3D Fermi surface at Γ-point as the carrier concentration changes by two orders of magnitude (10$^{17}$ to 10$^{19}$cm$^{-3}$). In high magnetic fields, the Nernst response displays giant quantum oscillations indicating that this feature is not exclusive to compensated semi-metals. A comprehensive analysis of the Landau Level spectrum firmly establishes a large $g$-factor in this material and a substantial decrease of the Fermi energy with increasing magnetic field across the quantum limit. Thus, the presence of bulk carriers significantly affects the spectrum of the intensively debated surface states in Bi2Se3 and related materials.