Open AccessMolecular dynamics simulation of heterogeneous adatom diffusion on Cu（001） surface
Author(s) -
Meng Li-Juan,
Rongwu Li,
Shaojun Liu,
Sun Jun-Dong
Publication year - 2009
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
ISSN - 1000-3290
DOI - 10.7498/aps.58.2637
Subject(s) - diffusion , arrhenius equation , surface diffusion , materials science , chemical physics , activation energy , molecular dynamics , effective diffusion coefficient , jump diffusion , lattice diffusion coefficient , diffusion process , jump , thermodynamics , chemistry , computational chemistry , physics , adsorption , innovation diffusion , medicine , knowledge management , radiology , quantum mechanics , computer science , magnetic resonance imaging
The diffusion processes of single adatoms Ag,Pd and Cu on Cu001 surface are investigated by molecular dynamics. By observing the mechanisms of selfdiffusion and heterogeneous diffusion, the diffusion frequencies of three kinds of adatoms under different temperatures are counted and diffusion barriers and the preexponential factors of diffusion frequency are fitted. The results of diffusion barriers are compared with those from the static calculation. The results show that: Under 800 K, the dominant diffusion mechanism of adatom Ag,Pd and Cu is the simple hopping mechanism. The hopping frequency of adatom Ag is the biggest, and that of adatom Pd is the smallest. For homogeneous and heterogeneous adatom diffusion processes, the relationship between diffusion frequency and temperature obeys the Arrhenius formula. The diffusion barriers fitted from Arrhenius formula are relevant to the surface structure and the cohesive energy of adatom on the surface. The transition temperatures of diffusion from the jumpmechanismdominant to the exchangemechanismdominant are about 825 K and 937 K for Pd and Cu adatoms respectively.