Abstract

The scanning tunneling microscope (STM) provides a direct method to image atomic scale features on surfaces.¹ We describe a new methodology for performing STM which allows us to delineate electronic and geometric contributions to STM images so as to produce spatially- and energy-resolved images of surface state wave functions.² This new approach allows both topographic and spectroscopic data to be obtained simultaneously and is applied to study the Si(100) 2 × 1 and Si(111)7 × 7surfaces. We present images of the occupied and unoccupied surface state orbitals of these surfaces and directly relate them to the underlying surface atomic positions. These energy resolved states are not only shown to correspond directly to those obtained in normal and inverse photoemission studies, but to be localized to specific atomic sites in these unit cells. The applicability of this approach to study isolated or extended surface defects and/or adsorbed molecules will also be discussed.

© 1986 Optical Society of America