研究目的
To study the diffusion of heterogeneous ternary (Cu‐Ag‐Zr) adatoms clusters on Ag(111) surface using molecular dynamics techniques for applications in thin film formation.
研究成果
The diffusion rate of ternary heterogeneous adatoms clusters increases with temperature and decreases with cluster size. Key mechanisms include hopping, sliding, shearing, atomic exchange (especially for Zr adatoms), pop-up of atoms, and vacancy-related processes at higher temperatures. These findings are significant for understanding and improving the formation and stability of ternary alloy-based thin films.
研究不足
The study is limited to molecular dynamics simulations with specific EAM potentials, which may not fully capture all quantum effects or experimental conditions. The simulations are conducted at fixed temperatures and for specific cluster sizes, potentially not covering all possible scenarios or material systems. The use of periodic boundary conditions and fixed bottom layers might introduce artifacts not present in real surfaces.
1：Experimental Design and Method Selection:
Molecular dynamics simulations were employed using the LAMMPS package with Embedded Atom Method potentials to model interactions. The system's total energy was calculated based on pair interactions, embedded functions, and density functions. The Nose Hoover thermostat was used to maintain constant temperature, and the velocity Verlet algorithm for solving equations of motion with a 1-fs time step.
2：Sample Selection and Data Sources:
An Ag substrate with an fcc lattice (lattice constant 4.09 ?) was generated, containing 14,986 Ag atoms in a rectangular block with dimensions 80 ? along [1 1 2] and [1 1 0] directions and 40 ? along [1 1 1] direction. Ternary adatoms clusters (trimer, hexamer, nonamer, decamer) composed of Cu, Ag, and Zr atoms were placed on the surface at fcc sites.
3：09 ?) was generated, containing 14,986 Ag atoms in a rectangular block with dimensions 80 ? along [1 1 2] and [1 1 0] directions and 40 ? along [1 1 1] direction. Ternary adatoms clusters (trimer, hexamer, nonamer, decamer) composed of Cu, Ag, and Zr atoms were placed on the surface at fcc sites.
List of Experimental Equipment and Materials:
3. List of Experimental Equipment and Materials: Computational software packages including LAMMPS for molecular dynamics simulations and VMD for visualization. No physical equipment was used as it is a simulation-based study.
4：Experimental Procedures and Operational Workflow:
The substrate was relaxed using the conjugate gradient method. The system was heated for 200 ps using NPT ensemble and thermalized with NVT ensemble to achieve constant temperatures (300, 500, 700 K). Adatoms clusters were adsorbed, and their dynamics were recorded over 3.5 ns simulation time. Snapshots were taken every 0.05 ps for analysis.
5：5 ns simulation time. Snapshots were taken every 05 ps for analysis.
Data Analysis Methods:
5. Data Analysis Methods: The diffusion coefficient was calculated using the mean square displacement of the center of mass. Potential energy variations and traces of center of mass were plotted to analyze diffusion mechanisms. Visual inspection of snapshots was used to identify specific diffusion processes like hopping, sliding, exchange, etc.
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