Superconducting transitions of intrinsic arrays of weakly coupled one-dimensional superconducting chains: the case of the extreme quasi-1D superconductor Tl2Mo6Se6

Authors: B Bergk, A P Petrovic, Z Wang, Y Wang, D Salloum, P Gougeon, M Potel and R Lortz

Published in: New Journal of Physics 13, 103018, 2011.

Tl2Mo6Se6 represents a model system for quasi-one-dimensional (quasi-1D) superconductors. We investigate its superconducting transition in detail  by  means  of  electrical  transport  experiments  on  high-quality  single crystalline  samples  with  onset  T c = 6.8 K.  Our  measurements  indicate  a highly  complex  superconducting  transition  that  occurs  in  different  stages, with  a  characteristic  bump  in  the  resistivity  and  distinct  plateau  structures in the supercurrent gap imaged by V –I  curves. We interpret these features as  fingerprints  of  the  gradual  establishment  of  global  phase coherence in  an  array  of  weakly  coupled  parallel  1D  superconducting  bundles.  In this  way,  we  demonstrate  that  superconducting  Tl 2 Mo 6 Se 6 behaves  like  an intrinsic  array  of  proximity  or  Josephson  junctions,  undergoing  a  complex superconducting phase-ordering transition at 4.5 K that shows many similarities to the Berezinskii–Kosterlitz–Thouless transition.

DOI: 10.1088/1367-2630/13/10/103018