Ge(001)-(2 1 0 3)-Pb <-> (2 1 0 6)-Pb: low-temperature two-dimensional phase transition
Abstract
The Ge(001)-(2 1 0 3)-Pb surface reconstruction with a lead coverage of 5/3 monolayer is on the borderline between the low-coverage covalently-bonded and high-coverage metallic lead overlayers. This gives rise to an unusual low-temperature phase transition with concomitant changes in the bonding configuration. Both the room-temperature and low-temperature phases of this system were investigated by surface x-ray diffraction using synchrotron radiation. The room-temperature Ge(001)-(2 1 0 3) phase is best described by a model with dynamically flipping germanium dimers underneath a distorted Pb(111) overlayer with predominantly metallic properties. In the low-temperature Ge(001)-(2 1 0 6) phase the dimers are static and the interaction between adsorbate and substrate and within the adsorbate is stronger than at room temperature. These results suggest that the phase transition is of order-disorder type.
Keywords
Cite
@article{arxiv.cond-mat/0107193,
title = {Ge(001)-(2 1 0 3)-Pb <-> (2 1 0 6)-Pb: low-temperature two-dimensional phase transition},
author = {O. Bunk and M. M. Nielsen and J. H. Zeysing and G. Falkenberg and F. Berg-Rasmussen and M. Nielsen and C. Kumpf and Y. Su and R. Feidenhans'l and R. L. Johnson},
journal= {arXiv preprint arXiv:cond-mat/0107193},
year = {2007}
}
Comments
18 pages including 6 figures and 3 tables