Surface diffusion of gold on quasihexagonal-reconstructed Au(100)

Abstract

The scanning tunneling microscope has been used to measure the saturation island density ${N}_{x}$ of gold on the hex-reconstructed Au(100) surface over a range of temperatures starting at 76 K. Assuming that the critical island size equals one, \ensuremath{\partial}ln${N}_{x}$/\ensuremath{\partial}(1/$T$) = $\ensuremath{\chi}{E}_{d}$/$k$, where $\ensuremath{\chi}$ is the scaling exponent, ${E}_{d}$ gives the activation energy for surface diffusion, and $k$ is the Boltzmann constant. The scaling exponent $\ensuremath{\chi}$ has been obtained as 0.26 $\ifmmode\pm\else\textpm\fi{}$ 0.03 from measurements of the island density as a function of the deposition rate, indicating that diffusion is indeed one-dimensional (anisotropic) and the critical island size is unity. We therefore derive an activation energy of 0.32 $\ifmmode\pm\else\textpm\fi{}$ 0.02eV and a frequency prefactor of 2(\ifmmode\times\else\texttimes\fi{}4${}^{\ifmmode\pm\else\textpm\fi{}1}$) \ifmmode\times\else\texttimes\fi{} 10${}^{13}$ s${}^{\ensuremath{-}1}$ for diffusion of gold on hex-reconstructed Au(100).