The fcc metals gold, silver, platinum and palladium absorb and form surfilce alloys with the bee transition metal molybdenum, although they do not form bulk alloy with molybdenum. The surface of bulk molybdenum is unstable and readying reconstructs to a c(2x2), we found that it is also possible for the surface to form a c(2x2) surface vacancy. The Density of States ( DOS ) of surface atoms of a p(1x1) Mo(100) show a peak near the Fermi Energy, rather than a dip of those atoms which are beneath the surface. The very stable surface alloys of Au/Mo(100), Ag/Mo(100), Pt/Mo(100) and Pd/Mo(100) are due to the quenching of the surface state near the Fermi level by chemical bonding between the fcc metal and the surface Mo atoms. The high surface DOS near E_F of molybdenum can be quenched in two...[ Read more ]

The fcc metals gold, silver, platinum and palladium absorb and form surfilce alloys with the bee transition metal molybdenum, although they do not form bulk alloy with molybdenum. The surface of bulk molybdenum is unstable and readying reconstructs to a c(2x2), we found that it is also possible for the surface to form a c(2x2) surface vacancy. The Density of States ( DOS ) of surface atoms of a p(1x1) Mo(100) show a peak near the Fermi Energy, rather than a dip of those atoms which are beneath the surface. The very stable surface alloys of Au/Mo(100), Ag/Mo(100), Pt/Mo(100) and Pd/Mo(100) are due to the quenching of the surface state near the Fermi level by chemical bonding between the fcc metal and the surface Mo atoms. The high surface DOS near E_F of molybdenum can be quenched in two ways, namely the formation of a c(2x2) surface vacancy array, and the formation of a c(2x2) surface alloy. We found high surface DOS near E_F of molybdenum that reappears in a cyclic deposition of monolayers of silver or gold as the absorbate, which has been observed in previous experiments. We found that for platinum and palladium, the surface high DOS neax E_F persists for coverage over 0.5 monolayers. The surface atoms of clean Mo(100) are displaced in the [11] direction in the c(2x2) reconstruction, in very good agreement with experimental results. It is both interesting and surprising to find that such a reconstruction survives when the Mo surface is covered by a full monolayer of Au. The displacement of the "subsurface" reconstruction is even larger in magnitude than the case of the clean surface.