Tuning of Electrical and Magnetic Transport Properties in Bi2Se3 Topological Insulator Crystals Doped with Mn

Mn (x) Bi2-x Se-3 crystals were grown by self-flux method and the phase structure, electrical and magnetic transport properties, carrier density, and Hall mobility were studied. Conductivity was modified by Mn at different temperature regions with different mechanisms. Samples containing low concentration of Mn with x a parts per thousand currency sign 0.05 showed metal behavior. It became p-type semiconductor at x = 0.07, where the electrical resistivity abruptly increased and the carrier density suddenly dropped. The nonmetallic behavior may originate from the topological transport properties or the reduction of intrinsic defects. Doping Mn resulted in a paramagnetic behavior and the origin of magnetism may be also related to the exchange interaction between Mn ions. Furthermore, obvious Shubbiknov-de-Haas (SdH) oscillations were only found in sample with x = 0.07.