Generalised coexistence of a low work function and a stable surface: CaAl4 and BaAuIn3

Cathodes are used in many devices ranging from microwave ovens to organic light-emitting diodes (OLEDs). Crucial materials properties are a low work function (Φ) and a (relatively) stable surface. The relation between the two was not clear for more-complex metals. Our previous paper [M.A. Uijttewaal, G.A. de Wijs, R.A. de Groot, R. Coehoorn, V. van Elsbergen, C.H.L. Weijtens, Chem. Mater. 17 (2005) 3879] predicted, on the basis of results on BaAl₄, that stable low-work-function surfaces are more general for intermetallic compounds with polar surfaces. This paper strengthens the prediction by first-principles calculations on various surfaces of CaAl₄ and BaAuIn₃.