Development of Modified Embedded Atom Method for Alkali Metals

The modified embedded atom method (MEAM) can describe the physical properties of bulk systems for a wide range of advanced engineering materials. However, the MEAM is found to return negative surface energy for Li(100), Li(110) and Li(111), if the relaxation of atomic positions on the surface is taken into account. In order to solve this problem, a new scheme of MEAM for lithium has been developed, by modifying the expression of embedding function. In this work, the new scheme is also applied to the other alkali metals, and the parameter sets of MEAM have been determined by fitting to not only bulk properties but also some non-bulk properties. The new MEAM potentials for alkali metals have been applied to calculate the elastic stiffness of crystal, the vacancy formation energy, the surface energies for low index crystal faces and the bond length and the binding energy for dimer. The results have been compared with experimental values.

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Molecular Dynamics Studies of Thin-Films of Sn On Cu

MRS Proceedings ◽

10.1557/proc-492-43 ◽

1997 ◽

Vol 492 ◽

Cited By ~ 6

Author(s):

R. Ravelo ◽

J. Aguilar ◽

M. I. Baskes

Keyword(s):

Thin Films ◽

Molecular Dynamics ◽

Melting Temperature ◽

Embedded Atom Method ◽

Interaction Potentials ◽

Embedded Atom ◽

Evolution Dynamics ◽

Modified Embedded Atom Method ◽

Experimental Values ◽

Diffusion Activation

ABSTRACTUsing Molecular Dynamics, the evolution dynamics of Sn on the (111) and (100) surfaces of Cu have been investigated as a function of coverage and temperature. The interaction potentials are described by modified embedded atom method (MEAM) potentials. The calculated diffusion activation energies of Cu in Sn and Sn in Cu agree reasonably well with experimental values. We find that the structure of the overlayer depends on the morphology of the substrate and remains stable up to temperatures of the order of 70% of the melting temperature of the substrate at which diffusion of Sn into the substrate and Cu atoms onto the overlayer is observed.

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Atomistic Simulation Study of Controlled Nanostructure Patterning

MRS Proceedings ◽

10.1557/proc-775-p9.27 ◽

2003 ◽

Vol 775 ◽

Cited By ~ 1

Author(s):

Byeongchan Lee ◽

Kyeongjae Cho

Keyword(s):

Diffusion Barrier ◽

Atomistic Simulation ◽

Degrees Of Freedom ◽

Embedded Atom Method ◽

Surface Kinetics ◽

Bulk Properties ◽

Embedded Atom ◽

Kinetics Of ◽

Dissociation Barrier ◽

Strain Dependent

AbstractWe investigate the surface kinetics of Pt using the extended embedded-atom method, an extension of the embedded-atom method with additional degrees of freedom to include the nonbulk data from lower-coordinated systems as well as the bulk properties. The surface energies of the clean Pt (111) and Pt (100) surfaces are found to be 0.13 eV and 0.147 eV respectively, in excellent agreement with experiment. The Pt on Pt (111) adatom diffusion barrier is found to be 0.38 eV and predicted to be strongly strain-dependent, indicating that, in the compressive domain, adatoms are unstable and the diffusion barrier is lower; the nucleation occurs in the tensile domain. In addition, the dissociation barrier from the dimer configuration is found to be 0.82 eV. Therefore, we expect that atoms, once coalesced, are unlikely to dissociate into single adatoms. This essentially tells that by changing the applied strain, we can control the patterning of nanostructures on the metal surface.

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