MANIPULATING CHLORINE ATOM BONDING ON THE SI(100)-(2X1) SURFACE WITH THE STM

Chlorine atoms strongly chemisorbed at dangling bond sites on the Si(1 00)-(2x1) surface are observed by scanning tunneling microscopy (STM) to hop between adjacent sites. The origin of this behavior is suggeste d to be an interaction between the field of the probe tip and the dipo le moment of the silicon-chlorine bond. Chlorine atom migration is sho wn to be facilitated by the presence of a metastable chlorine bridge-b onded minimum. The STM probe was used to excite single chlorine atoms into this bridging configuration, resulting in a local population inve rsion. Selective application of voltage pulses between the probe tip a nd the surface rearranged the local bonding and induced transformation s between different types of chlorine sites. In this manner, adsorbed species can be dissected and their composition and structure directly probed.