GEOMETRICAL STRUCTURE OF THE BI GAP (110) INTERFACE - AN X-RAY STANDING-WAVE TRIANGULATION STUDY OF A NONIDEAL SYSTEM/

The locally ordered structure formed by one monolayer of Bi on GaP (11 0) is studied by x-ray standing wave triangulation applied to three Br agg planes. This system has a larger lattice mismatch than other V/III -V interfaces (e.g., Sb/GaAs, Sb/InP, and Bi/InP), and does not grow e pitaxially as those other systems. Prior scanning tunneling microscopy studies of the Bi/GaP interface show that Bi grows in chains along th e (110BAR) direction interrupted by vacancies. The large difference in the atomic radii induces the formation of vacancies to allow relaxati on. Nevertheless, our results indicate that the interface structure re sembles the epitaxial continued layer structure, as in the better matc hed systems.