Energy splitting of image states induced by the surface potential corrugation of InAs(111)A

Abstract

By means of scanning tunneling spectroscopy (STS) we study the electronic structure of the III-V semiconductor surface InAs(111)A in the field emission regime (above the vacuum level). At high sample bias voltages (approaching +10 V), a series of well defined resonances are identified as the typical Stark shifted image states that are commonly found on metallic surfaces in the form of field emission resonances (FER). At lower bias voltages, a more complex situation arises. Up to three double peaks are identified as the first three FERs that are split due to their interaction with the periodic surface potential. The high corrugation of this potential is also quantified by means of density functional theory (DFT) calculations. Another sharp resonance not belonging to the FER series is associated with an unoccupied surface state.