Electronic structure of ErAs(100)

The experimental band structure of the rare-earth pnictide erbium arsenide (ErAs), grown epitaxially on GaAs(100), has been mapped out using photoelectron spectroscopy and inverse photoemission spectroscopy. The electronic structure is dominated by bulk bands qualitatively consistent with the calculated band structure. A number of additional nondispersing 4f multiplet levels can be identified in the valence-band structure as well as at least one surface resonance band. From symmetry selection rules, photoemission provides strong evidence that the Delta(5) (or e) symmetry bands are a consequence of hybridization between Er and As, while the Delta(1) (or a(1)) symmetry bands have possible contributions from nonbonding or antibonding states from Er (and/or As).