mk-STM study of Cu$_{0.2}$Bi$_{2}$Se$_{3}$ with W and Nb Tips

The Cu intercalated Bi$_{2}$Se$_{3}$ is predicted to be a time-reversal invariant topological superconductor with Majorana bound state in the vortex core. The samples are characterized by intrinsic inhomogeneity and disorder. Using mk-STM, a variety of high resolution superconducting gaps and sub-gap structures were observed. Our data from SIN and SIS junctions, using W and Nb tips on Cu$_{0.2}$Bi$_{2}$Se$_{3}$ and while applying of a magnetic field will be discussed in details.