Energetics of Sr adatom interactions on the Mo(112) surface

Abstract

First-principles methods are used to investigate the formation and structure of the ordered phases of Sr atoms adsorbed on the furrowed Mo(112) surface. The energetics of various commensurate and incommensurate adatom structures providing information on lateral interactions between adatoms is determined for coverages 0.11⩽Θ⩽1 monolayer. It is found that the binding energy of Sr atoms decreases with increasing coverage. The experimentally observed p(8×1) and p(5×1) adatom chains are found to belong to the most favored structures for Θ<0.5. The energetic difference between these two structures amounts to 20meV. The experimental work function variation with Sr adatom coverage is very well reproduced. The energy barriers for Sr diffusion along the atomic troughs are calculated and discussed.