Quantum size effects in α-plutonium (020) surface layers

•A density functional theory based study of the (020) surface of α-plutonium.•The surface modeled by a periodic slab consisting of up to ten atomic layers.•The total and cohesive energies indicate decreasing and increasing slopes.•The surface energy, unlike work function, exhibit significant oscillatory pattern.•The 5f electron density of states indicates progressive delocalization.

We present a systematic first principles density functional theory (DFT) based study of the (020) surface of α-plutonium using the projector-augmented-wave formalism as implemented in the Vienna Ab Initio Simulation Package (VASP). The surface was modeled by a periodic slab geometry comprised of anti-ferromagnetic atomic layers, with a thickness of up to ten atomic layers. The total and cohesive energies indicate a monotonically decreasing and increasing slope to the bulk values, respectively. The surface energies, in contrast to the work functions, exhibit a significant oscillatory pattern indicating persistent quantum size effects and possible magnetic frustration as well as other effects. The 5f electron density of states indicates progressive delocalization with increasing slab thickness.