2003/03/20 by Junren Shi, Biao Wu, X. C. Xie +2
Physics and Astronomy · #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevlett.91.076103
published as Phys. Rev. Lett. 91, 076103 (2003) · 4 pages, 5 figures
arxiv created 2003/03/20 · arxiv updated 2009/11/30
We propose that the indirect adatom-adatom interaction mediated by the conduction electrons of a metallic surface is responsible for the √(3)× √(3)⇔ 3× 3 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 √(3)× √(3)⇔ 3× 3 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.