Influence of 4f electronic states on the surface states of rare-earth hexaborides

We study the surface electronic structure of a series of rare-earth hexaborides using state-of-the-art high resolution photoemission spectroscopy. Experimental results reveal a surface state around 1.8 eV binding energy in all the hexaborides indicating its generic nature in this class of compounds. The surface and bulk electronic structures near the Fermi level, epsilon(F) are almost similar in each of the compounds. This suggests an interesting possibility of fabricating new materials possessing low work function like LaB6 where the behavior of mobile electrons can be tuned by rare-earth substitutions.