Heteroepitaxial growth of LiCl on Cu(001)

Thin film growth of LiCl on a Cu(001) substrate is studied using reflection high-energy electron diffraction and Auger electron spectroscopy. A LiCl film was found to grow heteroepitaxially on a Cu(001) substrate. At a substrate temperature of 300 K, a single-domain LiCl film ([100]_film//[110]_substrate) grows in a layer-by-layer fashion, while a double-domain LiCl film ([100]_film//[100]_substrate and [100]_film//[110]_substrate) grows at substrate temperatures higher than 470 K. The density-functional calculations are performed for model clusters in order to investigate the initial adsorption structure. It is found in the calculation that the LiCl island is adsorbed more stably on the fourfold hollow site of the first Cu layer than on the atop site. The effective charge of Li and Cl of the LiCl molecule decreases with adsorption on Cu(001), due to the shielding by Cu 4s and 4p free electrons.