Theoretical Study of Silicon Adatom Transfer from the Silicon Surface in Scanning Tunneling Microscopy

Abstract

We have investigated the electronic structures of a silicon adatom displaced from a silicon surface with the tip of a scanning tunneling microscope using the recursion-transfer-matrix method. This method is an effective means of calculation for electronic states of a bielectrode system under electric field and current. The adiabatic potential surfaces of the adatom moving from the surface to the tip and the corresponding induced electron density distributions are presented for several values of bias voltage. A decrease in the activation barrier height is seen for both positive and negative bias cases when the tip-surface distance is 11 bohrs, while a monotonous decrease is seen only for the positive bias case at a tip-surface distance of 8 bohrs.