Interplay between topological surface states and superconductivity in SmB6/NbN tunneling junction

Superconductivity and topological surface states are both exotic macro-quantum states in condense matter system. We could acquire a lot of new interesting quantum excitations if we let above two quantum states interplay in some appreciate way, such as topological superconductivity and Majorana fermion excitations. In this paper, we mainly study the interplay between Cooper pairs in superconductor NbN and topological surface states in SmB6 through magneto-transport and tunneling spectroscopy. Non-monotonic linear magnetoresistance(MR) was observed at low temperature. MR of NbN/SmB6 junction is positive as B<2T, however, MR turns to negative B>2 T. We predicated exotic interplay between Cooper pairs and topological surface states probably result in above special MR behaviors.