ADSORPTION AND DIFFUSION OF SILVER ON SIC(111) AND ZRC(111) SURFACES: A FIRST PRINCIPLES STUDY

First-principles calculation have been implemented to investigate the adsorption and diffusion behaviors of Ag atom on beta-SiC(111) and ZrC(111) surfaces. The configurations of Ag adsorbed on FCC site of beta-SiC(111) surface and ZrC(111) surface have strongest stability and the adsorption energies of these two configurations were -2.775 eV and -3.192 eV, respectively. The electronic structures of these two most stable configurations were analyzed by charge density difference (CDD) plots and particle density of states (PDOS), and the results shows that there are strong interactions between the Ag atom and surface atoms, indicating chemical bonds are formed between the Ag atom and surface Si atoms or Zr atoms. The surface diffusion barriers and minimum energy paths (MEP) were determined by climbing image nudged elastic band (CI-NEB) method. The results suggest that the energy barriers of Ag atom diffused from the FCC site to the neighboring FCC site are 0.166 eV for beta-SiC(111) surface and 0.150 eV for ZrC(111) surface. The surface diffusion coefficients of Ag atom on beta-SiC(111) and ZrC(111) surfaces at 1273 K are 4.035x10(-8) m(2)/s and 2.503x10(-8) m(2)/s, respectively. The surface diffusion coefficient results indicate that it is easier for Ag atom diffuses on beta-SiC(111) than on ZrC( 111) surface.