Atomic sized contacts and electronic transport in 𝛂-Sn

Tin has two allotropic crystalline forms, below 13°C changes its structure into the white form (𝞪-Sn). Under tensile or compressive strain it behaves as a topological insulator or Dirac semimetal respectively[1][2]. In this work we studied atomic sized contacts through electronic transport in 𝞪-Sn, using STM-BJ under cryogenic vacuum. Traces of conductance were obtained in the process of stretching a tin wire. We found that these would be distributed in three different groups when they are sorted by a clustering-machine learning tool[3].

Conductance spectroscopic curves were obtained at the last stages of rupture of the wire, showing different behaviors depending on the trace.

These preliminary results show the richness of scenarios of the electronic transport properties of tin at the atomic scale that could indicate a strong dependence on directionality and local-crystal orientation.