Adsorption of thin films of titanium on tungsten (111) surface

The structural and electronic properties of titanium-covered (111) surface of tungsten are studied via first-principles density-functional calculations. The dominant role played by substrate-adlayer interactions in the formation of thin films of Ti on W(111) explains the observed isomorphous growth for Ti depositions up to a full physical overlayer, with adatoms most favorably arranged in substrate-lattice-continuation sites. The optimized atomic configurations indicate substantial interplane relaxations following the contraction-contraction-expansion pattern, characteristic also of the clean W(111) substrate. Modification of the surface electronic properties of the Ti/W(111) system is examined for increasing adsorbate coverage with emphasis placed on the formation and localization properties of adsorbate-induced resonances.