title: Direct observation of sn adatoms dynamical fluctuations at the Sn/Ge(111) surface.
abstract: The well-known low-temperature phase transition sqrt[3]xsqrt[3] to 3x3 for the 1/3 monolayer of Sn adatoms on the Ge(111) surface has been studied by scanning tunneling microscopy. The STM tip was used as a probe to record the tunneling current as a function of time on top of the Sn adatoms. The presence of steps on the current-time curves allowed the detection of fluctuating Sn atoms along the direction vertical to the substrate. We discuss the effect of temperature and surface defects on the frequency of the motion, finding consistency with the dynamical fluctuations model.
authors.affiliation: CNR-Istituto di Struttura della Materia, via del Fosso del Cavaliere 100, I-00133 Roma, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Ronci
authors.forename: Stefano
authors.initials: S
authors.lastname: Colonna
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Thorpe
authors.forename: Antonio
authors.initials: A
authors.lastname: Cricenti
authors.forename: Guy
authors.initials: G
authors.lastname: Le Lay