RESTORATION OF STM IMAGES DISTORTED BY TIME-DEPENDENT PIEZO DRIVER AFTEREFFECTS

STM images recorded with piezoelectric drivers show characteristic distortions at the boundaries where the tip motion is reversed. Such artifacts can be eliminated by correcting for aftereffect assuming a logarithmic time-dependence. The amplitudes of such terms and the time elapsed between scan direction reversal and scan recording can be estimated by visual inspection of the corrected scan image on a graphics display and by maximizing picture correlation functions. STM images of well ordered clean single-crystal gold and copper surfaces are satisfactorily restored with this procedure.