Te thin films grown by molecular beam epitaxy*

Sn_1-xIn_xTe is derived from the topological crystalline insulator SnTe which becomes superconducting when doped with Indium and it is one of the top candidates for topological superconductivity [1].

Sn_1-xIn_xTe films have been grown by molecular beam epitaxy on a Bi₂Te₃ buffer layer, which has a good lattice matching for the growth in the (111) direction [2]. Using in situ post-annealing procedures, we achieve robust superconductivity. To look for possible signatures of topological superconductivity, we fabricated tunnel junctions on the surface of the Sn_1-xIn_xTe films. The tunnelling spectroscopy data shows a two-gap structure in the conductance spectra which points to the coexistence of bulk and surface superconductivity in the studied films.

[1] S. Sasaki et al., Phys. Rev. Lett. 109, 217004 (2012)
[2] A.A. Taskin et al., Phys. Rev. B 89, 121302(R) (2014)