Effect of Sb substitution on the Topological Surface States in   Bi_{2}Se_{3} single crystals: a magneto-transport study
  Magneto-transport measurements have been carried out on Bi2-xSbxSe3 (x = 0, 0.05, 0.1, 0.3, 0.5) single crystals at 4.2 K temperature in the magnetic field range of -15 T to 15 T. Shubnikov-de Haas (SdH) oscillations of 2D nature were observed in samples with Sb concentration upto x = 0.3. The analyses of SdH oscillations observed in magneto-resistance data using Lifshitz-Kosevich equation reveal a systematic decrease in the Fermi surface area with Sb substitution. The Berry phase obtained from the Landau Level fan diagram suggests the occurrence of 2D oscillations arising from a Topological Surface State (TSS) for Sb concentrations of x = 0, 0.05 and 0.1; while 2D oscillation seen at higher Sb concentration is attributed to surface 2D electron gas consequent to downward band bending. 
T. R. Devidas, E. P. Amaladass, Shilpam Sharma, Awadhesh Mani, R.   Rajaraman, C. S. Sundar and A. Bharathi
cond-mat.mtrl-sci cond-mat.mes-hall