title: Low temperature scanning force microscopy of the Si(111)-(7x7) surface
abstract: A low temperature scanning force microscope (SFM) operating in a dynamic mode in ultrahigh vacuum was used to study the Si(111)- (7x7) surface at 7.2 K. Not only the twelve adatoms but also the six rest atoms of the unit cell are clearly resolved for the first time with SFM. In addition, the first measurements of the short range chemical bonding forces above specific atomic sites are presented. The data are in good agreement with first principles computations and indicate that the nearest atoms in the tip and sample relax significantly when the tip is within a few A of the surface.
authors.affiliation: Institute of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland.
authors.initials: MA
authors.lastname: Lantz
authors.initials: HJ
authors.lastname: Hug
authors.lastname: van Schendel PJ
authors.initials: R
authors.lastname: Hoffmann
authors.initials: S
authors.lastname: Martin
authors.initials: A
authors.lastname: Baratoff
authors.initials: A
authors.lastname: Abdurixit
authors.initials: H
authors.lastname: Guntherodt
authors.initials: C
authors.lastname: Gerber