Electrical and Magnetic Properties of Copper-Intercalated Topological Insulator Bi2Se3 Single Crystal

In this manuscript, the growth, structural characterization, electrical transport and magnetic properties of Cu-intercalated Bi2Se3 single crystals of excellent quality synthesized through an efficient two-step melt growth method are reported. The Cu0.1Bi2Se3 single crystals exhibit superconductivity due to Cu intercalation between two quintuple layers of Bi2Se3, which is also known as the van der Waals gap. The H-c2 versus T-c phase diagram obtained with the help of the electrical resistance measurements indicate that in the zero-temperature limit, the H-c2 can be as high as 27.1 kOe when the field is applied parallel to the c-axis, though the electrical transport is found to be highly anisotropic in nature. Estimation made on the basis of the present experimental results indicate that Cu0.1Bi2Se3 is a Pauli limited superconductor. In the superconducting state, the field dependence of magnetization seems to be consistent with a spin-triplet vortex state with odd parity. In the normal state, on the other hand, both the temperature dependence of magnetic susceptibility and the signature of the magnetoresistance indicate the presence of antiferromagnetic correlations in the sample.