Theoretical Study of c(2×2) Structure in Li/Al(001) System

Stability of Li/Al(001)-c(2×2) structure in which Li atoms are adsorbed substitutionally on Al(001) surface is studied by performing first-principles total-energy calculations. Our results for optimized structural parameters of the system are in reasonably good agreement with experiment. It is found that the c(2×2) structure is stabilized mainly due to a binding-energy gain of Li with Al atoms. Density of states of the c(2×2) structure of Li/Al(001) is compared with that of Na/Al(001) system to clarify bonding nature of alkali-atom adsorption.