First principles systematics of ordered metallic monolayers. I. Groups I and II through Sr

Density functional calculations, in the local density approximation, are reported for hexagonal monolayers of Li, Be, Na, Mg, K, Ca, Rb and Sr. In parallel with the well known study of bulk metals by Moruzzi, Janak, and Williams, the author calculate the equilibrium lattice parameter and the electronic properties at that configuration. Notable findings include the occurrence of both bond contraction and expansion, universal scaling of the equation of state, and densities of states at the Fermi level much larger than for bulk in Be and Sr. The possible existence and the characterisation of well localised surface states at Gamma in Mg, Ca and Sr somewhat analogous to the state already found both experimentally and theoretically in Be are considered in detail.