We report measurements of the surface Shubnikov de Haas oscillations (SdH) on
crystals of the topological insulator Bi2Te2Se. In crystals with large
bulk resistivity (∼4 Ωcm at 4 K), we observe ∼15 surface SdH
oscillations (to the n = 1 Landau Level) in magnetic fields B up to 45
Tesla. Extrapolating to the limit 1/B→0, we confirm the 21-shift
expected from a Dirac spectrum. The results are consistent with a very small
surface Lande g-factor.Comment: Text expanded, slight changes in text, final version; Total 6 pages,
6 figure