Resolving unoccupied electronic states with laser ARPES in bismuth-based cuprate superconductors
Research output: Contribution to journal › Article › Scientific › peer-review
|Number of pages||5|
|Journal||Physical Review B|
|Publication status||Published - 13 Feb 2015|
|Publication type||A1 Journal article-refereed|
Angle-resolved photoemission spectroscopy (ARPES) is typically used to study only the occupied electronic band structure of a material. Here we use laser-based ARPES to observe a feature in bismuth-based superconductors that, in contrast, is related to the unoccupied states. Specifically, we observe a dispersive suppression of intensity cutting across the valence band, which, when compared with relativistic one-step calculations, can be traced to two final-state gaps in the bands 6 eV above the Fermi level. This finding opens up possibilities to bring the ultrahigh momentum resolution of existing laser-ARPES instruments to the unoccupied electron states. For cases where the final-state gap is not the object of study, we find that its effects can be made to vanish under certain experimental conditions.