title: Correlated electromigration of H in the switchable mirror YH(3-delta)
abstract: Electromigration of hydrogen in YH(3-delta) is studied by exploiting the H concentration dependence of the optical transmission of YH(3-delta). We find the effective valence Z* of H in YH(3-delta) to be negative. Its value is dominated by a huge wind-force-like term, i.e., Z* approximately K/rho, with K approximately -60 mOmega cm. This value is 3 orders of magnitude larger than typical for H in metals. In an Arrhenius plot, the ratio of hydrogen and electron fluxes extrapolates to unity at infinite temperature, suggesting a one-to-one correlation of hydrogen and electron hopping. We discuss our results in the light of strong electron correlation theories which predict each proton to bind two electrons in a sort of Zhang-Rice singlet.
authors.affiliation: Faculty of Sciences, Division of Physics and Astronomy, Vrije Universiteit De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands.
authors.lastname: van Der Molen SJ
authors.initials: MS
authors.lastname: Welling
authors.initials: R
authors.lastname: Griessen