Single Crystal Growth and Transport Properties of Cu-doped Topological Insulator Bi2Se3

Abstract

We report on the growth of high quality single crystals of CuxBi2Se3 with x=0, 0.12 and 0.15, using Bridgman method. A study of crystal structure shows that the c-lattice parameter slightly decreases with an increasing level of Cu-doping. STM images indicate that both Cu-intercalation between Se-Se layers and Cu-substitution in Bi-layer sites are present. With dc magnetization measurements, superconducting transitions in Cu-intercalated Bi2Se3 have been found with a TC of 3.5 K for x∼0.12 and approximately 3.6 K for x∼0.15, respectively. The resistivity data show metallic behavior in the Bi2Se3 crystals and paramagnetic features are observed in the low temperature region of the Cu-doped samples.