title: Surface phase transitions induced by electron mediated adatom-adatom interaction.
abstract: We propose that the indirect adatom-adatom interaction mediated by the conduction electrons of a metallic surface is responsible for the sqrt[3]xsqrt[3]<==>3x3 structural phase transitions observed in Sn/Ge (111) and Pb/Ge (111). When the indirect interaction overwhelms the local stress field imposed by the substrate registry, the system suffers a phonon instability, resulting in a structural phase transition in the adlayer. Our theory is capable of explaining all the salient features of the sqrt[3]xsqrt[3]<==>3x3 transitions observed in Sn/Ge (111) and Pb/Ge (111), and is in principle applicable to a wide class of systems whose surfaces are metallic before the transition.
authors.affiliation: Condensed Matter Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: Junren
authors.initials: J
authors.lastname: Shi
authors.forename: Biao
authors.initials: B
authors.lastname: Wu
authors.forename: X C
authors.initials: XC
authors.lastname: Xie
authors.forename: E W
authors.initials: EW
authors.lastname: Plummer
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Zhang