title: Atomistic picture of charge density wave formation at surfaces.
abstract: We used ultrafast electron diffraction and density-functional theory calculations to gain insight into the charge density wave (CDW) formation on In/Si(111). Weak excitation by a femtosecond-laser pulse results in the melting of the CDW. The immediate freezing is hindered by a barrier for the motion of atoms during the phase transition: The melted CDW constitutes a long-lived, supercooled phase and is strong evidence for a first-order transition. The freezing into the CDW is triggered by preexisting adsorbates. Starting at these condensation nuclei, the CDW expands one dimensionally on the In/Si(111) surface, with a constant velocity of more than 80 m/s.
authors.affiliation: Department of Physics and Center for Nanointegration Duisburg-Essen, University Duisburg-Essen, D-47057 Duisburg, Germany. simone.wall@uni-due.de
authors.forename: Simone
authors.initials: S
authors.lastname: Wall
authors.forename: Boris
authors.initials: B
authors.lastname: Krenzer
authors.forename: Stefan
authors.initials: S
authors.lastname: Wippermann
authors.forename: Simone
authors.initials: S
authors.lastname: Sanna
authors.forename: Friedrich
authors.initials: F
authors.lastname: Klasing
authors.forename: Anja
authors.initials: A
authors.lastname: Hanisch-Blicharski
authors.forename: Martin
authors.initials: M
authors.lastname: Kammler
authors.forename: Wolf Gero
authors.initials: WG
authors.lastname: Schmidt
authors.forename: Michael
authors.initials: M
authors.lastname: Horn-von Hoegen