All-electron local-density theory of covalently bonded material adsorbed on metallic substrate: P(1×1) Si monolayer on W(001)

Results of self-consistent all-electron local-density-functional total-energy calculations of a Si monolayer on the W(001) surface employing the full-potential linearized augmented plane-wave method are presented. For an ordered p(1×1) overlayer of Si on the W(001) substrate we find a Si-W bond length of 2.59 A, which is very close to that of bulk WSi2 (2.62 A). Surprisingly, compared to that of the clean W(001) the work function is not changed appreciably as a result of the covalent bonding. The strong covalent bonding between the Si and W atoms is found to suppress the localized surface states of the clean W(001) surface. Si-W interface bonding states are found at the symmetry points and M in the surface Brillouin zone with binding energies of -10.5 and -7.8 eV, respectively.