Switching between coherent and incoherent electronic states

A quasi-one-dimensional surface resonance on the Pt(110)-(1×2) missing-row reconstructed surface is investigated by angle-resolved photoemission for different hydrogen coverages. On the H covered surface the one-dimensional (1D) electronic states located on the close-packed atom rows are shown to be phase-coherent resulting in a pronounced quasi-particle (QP) peak at EF. Desorption of hydrogen destroys the coherence, thus quenching the QP peak. The intensity is-partially inelastically-redistributed into a broad range of k space.