Electronic and magnetic structure of the (001) surfaces of V, Cr, and V/Cr

We investigate the magnetic and structural properties of the (001) surfaces of V, Cr, and one monolayer V on Cr in density-functional theory in the local spin-density and the generalized gradient approximation. For both exchange-correlation potentials the surface magnetic moment of Cr is very large (2.6 mu (B)) and the V surface is nonmagnetic. One monolayer V on Cr exhibits also a large magnetic moment (2.1 mu (B)) but reduces the Cr moment drastically. The importance of the surface moment on the spin-density wave of Cr is discussed. While some of the discrepancies between theory and experiment are cured by the generalized gradient corrections, several difficulties remain.