Thermal Contraction and Disordering of the Al(110) Surface

Nicola Marzari; David Vanderbilt; Alessandro De Vita; M. C. Payne

doi:10.1103/PhysRevLett.82.3296

Thermal Contraction and Disordering of the Al(110) Surface

Nicola Marzari, David Vanderbilt, Alessandro De Vita, and M. C. Payne

Phys. Rev. Lett. 82, 3296 – Published 19 April 1999

Abstract

Al(110) has been studied for temperatures up to 900 K via ensemble density-functional molecular dynamics. The strong anharmonicity displayed by this surface results in a negative coefficient of thermal expansion, where the first interlayer distance decreases with increasing temperature. Very shallow channels of oscillation for the second-layer atoms in the direction perpendicular to the surface support this anomalous contraction, and provide a novel mechanism for the formation of adatom-vacancy pairs, preliminary to the disordering and premelting transition. Such characteristic behavior originates in the free-electron-gas bonding at a loosely packed surface.

Received 16 June 1998

DOI:https://doi.org/10.1103/PhysRevLett.82.3296

Authors & Affiliations

Nicola Marzari^1,*, David Vanderbilt¹, Alessandro De Vita^2,3, and M. C. Payne⁴

¹Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854-8019
²INFM and Department of Material Engineering and Applied Chemistry, University of Trieste, I-34149 Trieste, Italy
³Institut Romand de Recherche Numérique en Physique des Matériaux, PPH-Ecublens, CH-1015 Lausanne, Switzerland
⁴Cavendish Laboratory (TCM), University of Cambridge, Madingley Road, Cambridge CB3 0HE, England