Imaging surface atomic structure by means of auger electrons

Area of Science:

• Surface Science
• Materials Science
• Solid-State Physics

Background:

• Auger electron emission from surfaces provides information about atomic composition and electronic states.
• Understanding electron emission patterns is crucial for surface analysis techniques.
• Previous theoretical models did not fully explain observed angular distributions.

Purpose of the Study:

• To investigate the complete angular distribution of Auger electrons emitted from platinum[111] single-crystal surfaces.
• To compare experimental results with theoretical simulations.
• To establish the utility of angular distribution Auger microscopy (ADAM) for surface imaging.

Main Methods:

• Experimental measurement of Auger electron angular distributions from platinum[111] surfaces.
• Theoretical simulations using atomic point emitters and spherical atomic scatterers.
• Imaging of silver and iodine monolayers on platinum[111] using ADAM.

Main Results:

• Discovery of "silhouettes" of surface atoms formed by Auger electron emission.
• Experimental results closely agreed with new theoretical simulations.
• New simulations contradicted previous theoretical predictions.
• Successful imaging of monolayer structures using ADAM.

Conclusions:

• Auger electron angular distributions reveal atomic "silhouettes," providing detailed surface information.
• Angular distribution Auger microscopy (ADAM) is a validated technique for interfacial structure imaging.
• ADAM is valuable for studying electron-solid interactions in various scientific and engineering fields.