Emission energy barriers of scandate surfaces with adsorbed Ba and Ba-O using density functional theory

摘要

Density functional theory was used to calculate the surface electron emission barriers for the stable (011) and (111) surfaces of bixbyite Sc2O3 in the presence of adsorbed Ba and Ba-O. A low surface barrier of 1.21 eV for a defected BaO monolayer on Sc2O3 (011) was found to be thermodynamically stable. This result provides a straightforward explanation of low effective work function measurements obtained for scandate cathodes.