Tight-Binding Analysis of Surface Electronic Conduction Measured with Micro-Multipoint Scanning Tunneling Microscopy Probes

摘要

To analyze electronic conduction through surface states in micro-multipoint measurements using scanning tunneling microscopy, we calculated electron density and current distribution in a surface with Tamm states of a simple cubic lattice using a tight-binding method with the Hueckel approximation. Both wave function and Green's function methods were employed in the calculations, and two peaks of the transmission spectrum were obtained at -1.10 and 2.91 eV using both methods. The analysis of current distribution revealed that the transmission at 2.91 eV mainly corresponds to surface state conduction, whereas that at -1.10 eV includes bulk state conduction. These results suggest that whether or not a measured conductance corresponds to pure surface state conduction is dependent on the energy of injected electrons.