PNNL

Abstract

First-principles calculations based on density functional theory with the generalized gradient approximation have been performed to study the aluminum (Al) adsorption on the (001) surface of a-uranium (a-U). The geometric, electronic and magnetic properties have been investigated at coverages of 0.25 and 0.5 monolayer. The results show that the quasi-trigonal sites are preferred at both coverages. The bonding of Al with U is found to be metallic, which mainly arises from the mixing of Al 3sp and U 5f states. A ferromagnetic phase is determined for the bare a-U(001) surface, while the adsorption of Al on the surface significantly perturbs the spin arrangement pattern and reduces the local magnetic moment, leading to a ferrimagnetic phase on the a-U(001) surface at the coverage of 0.5 monolayer. However, the Al overlayer is paramagnetic. Generally, the spin polarization has negligible effects on the geometric and electronic properties of Al atoms on the a-U(001) surface.