Searching for ideal topological superconductors in Pb-Sn-In-Te system*

The discovery of 3D topological insulator  materials and topological superconductor  open  up a new research field in the condensed matter physics.  In order to search for the topological superconductor, we have grown a large number of the single crystals of  Pb-system ( Pb-Sn-In-Te) topological crystalline insulator  and their topological superconductor .  We have measured the physical properties on these single crystals by various techniques. We have studied the effect of crystal growth condition, impurity and composition on the bulk electrical conductivity of these single crystals. We try to find out which composition and crystal growth condition is the best for the ideal topological insulator,  topological crystalline insulator and  topological superconductor.  We have got the bulk topological superconductor  with T_c=5K.