Density functional theory analysis of hexagonal close-packed elemental metal photocathodes

A density function theory based analysis of photoemission from hexagonal close packed (hcp) metals is presented and the calculated values of the rms transverse momentum (ΔpT) are in good agreement with the available experimental data on Be [Phys. Rev. Lett. 111, 237401 (2013)] and Mg [Proceedings of LINAC 2002, Gyeongju, Korea (2002)]. The lattice constants and work functions of the hcp metals are also examined and are consistent with the available experimental values. In addition, emission from (0001)-oriented Be is examined due to the presence of a strong surface state.