title: Evidence of Sn adatoms quantum tunneling at the alpha-Sn/Si(111) surface.
abstract: We present a low-temperature scanning tunneling microscopy study of the alpha-Sn/Si(111) surface that demonstrates the fluctuating behavior of the Sn adatoms. The dynamical fluctuation model, successfully applied in describing the alpha-Sn/Ge(111) surface, is proposed for the related alpha-Sn/Si(111) surface too, although with a much lower transition temperature. In addition, a new phenomenon appears responsible for the unexpected evidence that the average oscillation frequency remains constant at temperatures lower than 15 K, in contradiction to the Arrhenius law. We explain this phenomenon as quantum tunneling of Sn adatoms.
authors.affiliation: ISM CNR, Via del Fosso del Cavaliere 100, I-00133 Roma, Italy. ronci@ism.cnr.it
authors.forename: Fabio
authors.initials: F
authors.lastname: Ronci
authors.forename: Stefano
authors.initials: S
authors.lastname: Colonna
authors.forename: Antonio
authors.initials: A
authors.lastname: Cricenti
authors.forename: Guy
authors.initials: G
authors.lastname: Le Lay