ELECTRIC FIELD EFFECTS IN SCANNING TUNNELING MICROSCOPE IMAGING

We present a high-voltage extension of the Tersoff-Hamann theory of sc anning tunneling microscope (STM) images, which includes the effect of the electric field between the tip and the sample. The theoretical mo del is based on first-principles electronic structure calculations and has no adjustable parameters. We use the method to calculate theoreti cal STM images of the monohydrate Si(100)-H(2x1) surface with missing hydrogen defects at -2V and find an enhanced corrugation due to the el ectric field, in good agreement with experimental images.