STM and STS Investigations of Bi₂Te₃ Surface

We carried out scanning tunneling microscopy/spectroscopy studies of Bi₂Te₃ surface, which, to the best of our knowledge, had not been attempted so far. We got images of surface of the material in many scales from micrometers to nanometers, which showed a layered structure of Bi₂ Te₃, with many monoatomic terraces. We found agreement between measured heights and corresponding bulk crystal structure derived from X-ray data. In nanoscale we obtained an atomic resolution. Using scanning tunneling spectroscopy we carried out examination of the electronic structure. We observed different I - V characteristics and contrast on current imaging tunneling spectroscopy maps on non equivalent terraces. The dI/dV (∼ density of states) curves referred to those terraces were compared with theoretically calculated by Larson et al. density of states derived from Bi p and Te-1 p orbitals. The analysis of our results allowed us to distinguish bismuth from tellurium planes.