title: Electron spectroscopy and scanning tunneling microscopy study of quasi-two-dimensional freezing at the liquid/vapor interface of Ga-Bi alloys.
abstract: We have studied the interfacial characteristics of Ga-rich liquid Ga-Bi alloys at various compositions and temperatures up to 300 degrees C by different electron spectroscopies under ultrahigh vacuum conditions. In particular, the thickness and thickness profiles of Bi-rich wetting and surface freezing films have been measured. It is found that at the surface freezing transition the Bi film thickness jumps from approximately 5 A to macroscopic values of over 100 A. This distinct behavior is discussed in comparison with the results in Ga-Pb. In addition, we report first scanning tunneling microscopy observations of the surface structure of a solidified Ga(0.989)Bi(0.011) alloy after passing a surface freezing transition. The topology at room temperature is characterized by extended, atomically flat Bi terraces covered by nanosized triangular two-dimensional Bi islands.
authors.affiliation: Institute of Physical Chemistry, University of Karlsruhe (TH), Kaiserstrasse 12, D-76128 Karlsruhe, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Issanin
authors.forename: A
authors.initials: A
authors.lastname: Turchanin
authors.forename: W
authors.initials: W
authors.lastname: Freyland