Electronic structure of yttrium hydride as a function of hydrogen concentration

Gunnar Garnier

Institut de Physique, Université de Neuchâtel, Rue Breguet 1, 2000 Neuchâtel, Switzerland

The electronic structure of metal hydrides is of great interest for the understanding of their peculiar properties, like the metal-insulator transition occuring between YH2 and YH3. We have studied both, experimentally and theoretically, using angle-resolved photoemission and density functional theory (DFT) band structure calculations, the evolution of the electronic structure of yttrium hydride as a function of the hydrogen concentration. The photoemission spectra exhibit drastic changes between the hydride, dihydride and trihydride yttrium phases. The simulations, performed for three hypothetical fcc yttrium hydride phases (Y, YH2 and YH3) reproduce partly the behaviour observed in photoemission.