Yttrium can be loaded with hydrogen up to high concentrations causing dramatic structural and electronic changes of the host lattice. We report on angle-resolved photoemission experiments of the Y trihydride phase. Most importantly, we find the absence of metal $d$ bands at the Fermi level and a set of flat, H-induced bands located at much higher binding energy than predicted, indicating an increased electron affinity at H sites.

• Received 26 July 2002

DOI:https://doi.org/10.1103/PhysRevLett.90.196804