Title: Anomalous transport properties in Nb/Bi1.95Sb0.05Se3 hybrid structure,
Abstract: We report the proximity induced anomalous transport behavior in a Nb
Bi1.95Sb0.05Se3 heterostructure. Mechanically Exfoliated single crystal of
Bi1.95Sb0.05Se3 topological insulator (TI) is partially covered with a 100 nm
thick Niobium superconductor using DC magnetron sputtering by shadow masking
technique. The magnetotransport (MR) measurements have been performed
simultaneously on the TI sample with and without Nb top layer in the
temperature,T, range of 3 to 8 K, and a magnetic field B up to 15 T. MR on TI
region shows Subnikov de Haas oscillation at fields greater than 5 T. Anomalous
linear change in resistance is observed in the field range of negative 4T to
positive 4T at which Nb is superconducting. At 0 T field, the temperature
dependence of resistance on the Nb covered region revealed a superconducting
transition (TC) at 8.2 K, whereas TI area showed similar TC with the absence of
zero resistance states due to the additional resistance from superconductor
(SC) TI interface. Interestingly below the TC the R vs T measured on TI showed
an enhancement in resistance for positive field and prominent fall in
resistance for negative field direction. This indicates the directional
dependent scattering of the Cooper pairs on the surface of the TI due to the
superposition of spin singlet and triplet states in the superconductor and TI
respectively.