BALLISTIC-ELECTRON-EMISSION MICROSCOPY ON COSI2 SI(111) INTERFACES - BAND-STRUCTURE INDUCED ATOMIC-SCALE RESOLUTION AND ROLE OF LOCALIZED SURFACE-STATES/

Applying a Keldysh Green's function method it is shown that hot electr ons injected from a scanning tunneling microscope tip into a CoSi2/Si( 111) system form a highly focused beam due to the silicide band struct ure. This explains the atomic resolution obtained in recent ballistic electron emission microscopy (BEEM) experiments. Localized surface sta tes in the (2 x I) reconstruction are found to be responsible for the also reported anticorrugation of the BEEM current. These results clear ly demonstrate the importance of bulk and surface band structure effec ts for a detailed understanding of BEEM data. [S0031-9007(98)07776-X].