Excited-state band mapping and momentum-resolved ultrafast population dynamics in In/Si(111) nanowires investigated with XUV-based time- and angle-resolved photoemission spectroscopy

Abstract

The electronic structure of a material can reveal a lot about its properties. Here, the authors map the electronic structure of the typically elusive excited states above the Fermi level throughout the full Brillouin zone in In/Si(111) nanowires. This allows for rigorous tests of current electronic structure calculation methods, and hints at a momentum-dependent excitonic coupling. In addition, extraction of the ultrafast population dynamics of these states and comparison with quasithermal modeling reveals a strongly nonequilibrium phonon distribution after photoexcitation.