A study was made of the temperature and orientation dependences of the field ion and electron emission and average work function for an emitter between 77 and 1800K. The results indicated that the (310) surface was thermally stable and had the lowest work function of any single crystal plane. This was confirmed by field emission retarding potential work-function (φ) measurements at 300K, which gave φ(310) = 2.50eV. The results showed that the relative orientation dependence of the room temperature work function was φ(310) < φ(210) < φ(100) < φ(110) < φ(111) < φ(211). This ordering was in accordance with the relative dipole contribution to the work function when surface reconstruction was included. The orientation dependence of the field electron emission was sensitive to field evaporation, thermal equilibration, and carbon contamination.

A Determination of the Low Work Function Planes of LaB6. Gesley, M., Swanson, L.W.: Surface Science, 1984, 146[2-3], 583-99