True atomic resolution imaging of surface structure and surface charge on the GaAs(110)

We demonstrated a novel method to detect the van der Weals and the electros tatic force interactions simultaneously on an atomic scale, which is based on frequency modulation detection method. For the first time, the surface s tructure and the surface charge at atomic-scale point defects on the GaAs(1 10) surface have been simultaneously resolved with true atomic resolution u nder ultra-high vacuum condition. From the bias voltage dependence of the i mage contrast, we can verify that the sign of the atomically resolved surfa ce charge at the point defect was positive. (C) 1999 Elsevier Science B.V. All rights reserved.