STS study of spectrum of surface electronic states in bismuth

Low temperature scanning tunneling spectroscopy of trigonal (0 0 0 1) plane and 'quasitrigonal' plane of twin interlayer on a cleaved bismuth surface is performed. It is found that both crystallographic planes are characterized by surface electron states with spectra exhibiting clearly defined singularities in the energy range ±1 eV. An analysis of the tunneling spectra has revealed the existence of a two-dimensional surface layer with a typical of metals density of electronic states