Photoemission of a quantum cavity with a nonmagnetic spin separator

Quantum well states are a consequence of confinement in a quantum cavity. In this study we investigate with photoemission the influence of the interface electronic structure on the quantum well state energy dispersion in ultrathin Mg(0001) films on W(110). Coupling between the sp-derived quantum well states and the substrate across the interface becomes manifest in a deviation from free electronlike dispersion behavior. Most importantly, we observe a marked level splitting, which is interpreted as due to the Rashba effect at the interface. Such an interfacial electron beam splitting on materials with strong spin-orbit coupling is an essential ingredient for novel spintronic devices. The combination of a quantum cavity with a heavy, electron reflecting substrate reveals spin-splitting effects in ultrathin films without conventional magnetism being involved.

Excited states mapped by secondary photoemission

We report on angle-resolved photoemission (ARPES) experiments on Cu(110) using Mg K(alpha) radiation. The secondary emission (SE) fine structure of electrons below 50 eV is found to map the empty band structure relevant for absolute band mapping in ARPES. The finding is based on a direct comparison of our experiments with very low-energy electron diffraction data [Phys. Rev. Lett. 81, 4943 (1998)]] recently shown to map the unoccupied states representing the photoemission final-state. This suggests a new theoretical approach to the SE process treating the outgoing electron state as the time-reversed diffraction state.

Electronic structure of the YH3 phase from angle-resolved photoemission spectroscopy

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.