Stability of two-dimensional nanostructures |
| |
Authors: | K Morgenstern E Laegsgaard I Stensgaard F Besenbacher M Böhringer W-D Schneider R Berndt F Mauri A De Vita R Car |
| |
Institution: | (1) Institute for Condensed Matter Physics, University of Lausanne, CH-1015 Lausanne, Switzerland (Fax: +41-21/692-3635, E-mail: karina.morgenstern@ipmc.unil.ch), CH;(2) Institute of Physics and Astronomy and Center for Atomic-scale Materials Physics, University of Aarhus, DK-8000 Aarhus C, Denmark, DK;(3) 2. Physikalisches Institut, RWTH Aachen, D-52056 Aachen, Germany, DE;(4) Institut Romand de Recherche Numérique en Physique des Matériaux, PPH-Ecublens, CH-1015 Lausanne, Switzerland, CH;(5) INFM and Dipartimento di Ingegneria dei Materiali, Università di Trieste, via A. Valerio 2, 34127 Trieste, Italy, IT |
| |
Abstract: | We investigate atomic and molecular nanostructures on metal surfaces by variable low-temperature scanning tunnelling microscopy.
In combination with molecular dynamics calculations we achieve a detailed understanding of the stability of these structures.?Atomic
nanostructures in homoepitaxial metallic systems are thermodynamically only metastable. Two-dimensional islands on Ag(110)
decay above a threshold temperature of T
l=175 K. Caused by the anisotropy of the surface, distinct decay behaviours exist above and below a critical temperature of
T
c=220 K. Calculations based on effective medium potentials of the underlying rate limiting atomic processes allow us to identify
the one-dimensional decay below T
c as well as the two-dimensional decay above T
c.?In contrast to atoms, the intermolecular electrostatic interaction of polar molecules leads to thermodynamically stable
structures. On the reconstructed Au(111) surface, the pseudo-chiral 1-nitronaphthalin forms two-dimensional supermolecular
clusters consisting predominantly of ten molecules. Comparison of images with submolecular resolution to local density calculations
elucidates the thermodynamical stability as well as the internal structure of the decamers.
Received: 25 March 1999 / Accepted: 17 August 1999 / Published online: 6 October 1999 |
| |
Keywords: | PACS: 61 16 Ch 68 60 Dv 82 30 Nr |
本文献已被 SpringerLink 等数据库收录! |
|