Fermi level tuning and weak localization/weak antilocalization competition of bulk single crystalline Bi(2-x)Sb(x)Se2Te compounds.

From the investigation of the electrical transport properties of single crystalline Bi(2-x)Sb(x)Se2Te (x = 0.0, 0.6, 0.8, 1.0, 1.2 and 1.4) compounds, we observed a systematic change of the Fermi level from n-type metallic (x = 0.0 and 0.6) or small-gap semiconducting (x = 0.8) to p-type semiconducting (x = 1.0) and metallic (x = 1.2 and 1.4), respectively, with increasing Sb-substitution concentration based on temperature-dependent electrical resistivity ρ(T) and Hall resistivity ρxy(H) measurements, respectively. The parent compound Bi2Se2Te exhibits linear negative magnetoresistance at low magnetic fields (H ⩽ 1 T) by weak localization. The intermediate doped compounds of x = 0.8 and 1.0 showed weak antilocalization (WAL) and weak localization (WL) crossover behavior from the field-dependent magnetoresistance measurements at low temperatures. From the Hikami-Larkin-Nagaoka analysis of the compounds (x = 0.8 and 1.0), we found that there is a competing behavior between WL and WAL in terms of Sb-doping and magnetic field strength.