Superconductivity and Superconductor-Insulator Transition in Single   Crystal Sb2Te3 Nanoflakes
  We report on transport properties of the topological insulator single crystal $Sb2Te3$ nanoflakes with thickness about from 7 to 50nm. A steep drop of resistance is appeared near $3K$ in the ultrathin $Sb2Te3$ nanoflakes, manifesting a superconducting transition.The magnetic field induced superconductor insulator transition of disordered 2D superconductor system is observed in the nanoflakes.The results show that the existence of certain optimum degree of disorder is a necessary condition for emergence of superconductivity.Temperature dependence of magneto-resistance shows a consecutive transformation of weak antilocalization cusp into the superconducting transition at low field when $B < BC$. 
Wei-Han Tsai, Chia-Hua Chien, Ping Chung Lee, Min-Nan Ou, Sergey R.   Harutyunyan, Yang-Yuan Chen
cond-mat.supr-con cond-mat.mes-hall