Al(110) has been studied for temperatures up to 900 K via ense mble density-functional molecular dynamics. The strong anharmonicity displayed by this surfa ce results in a negative coefficient of thermal expansion, where the first interlayer distance decr eases 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 n ovel mechanism for the formation of adatom-vacancy pairs, preliminary to the disordering and p remelting transition. Such characteristic behavior originates in the free-electron-gas bonding at a l oosely packed surface
Thermal Contraction and Disordering of the Al(110) Surface
DE VITA, ALESSANDRO;
1999-01-01
Abstract
Al(110) has been studied for temperatures up to 900 K via ense mble density-functional molecular dynamics. The strong anharmonicity displayed by this surfa ce results in a negative coefficient of thermal expansion, where the first interlayer distance decr eases 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 n ovel mechanism for the formation of adatom-vacancy pairs, preliminary to the disordering and p remelting transition. Such characteristic behavior originates in the free-electron-gas bonding at a l oosely packed surfacePubblicazioni consigliate
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