2018/08/23 by Stephan Michael, Hans Christian Schneider
Materials Science · Physics and Astronomy · #2D Materials and Applications #Atomic physics #Band gap #Condensed matter physics #Electronic and Structural Properties of Oxides #Excitation #Ga2O3 and related materials #Ion #Ionization #Laser #Materials science #Optics #Phonon #Physics #Quantum mechanics #Quasiparticle #Superconductivity #Ultrashort pulse #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.100.035431
published as Phys. Rev. B 100, 035431 (2019)
arxiv created 2018/08/23 · openalex created_date 2018/08/31 · openalex publication_date 2019/07/23 · arxiv updated 2019/07/31 · openalex updated_date 2026/08/05
For materials that exhibit dynamic changes in the electronic quasiparticle states after ultrafast optical excitation, it is extremely difficult to unambiguously separate quasiparticle band dynamics and carrier redistribution processes in state-of-the-art photoemission experiments. We study theoretically the interplay of band and carrier dynamics for a model system of a quasi-two-dimensional material with a small band gap and investigate the consequences for electronic distribution curves. Our model system contains photo-induced band-gap narrowing by a coherent phonon mechanism, which mimics the quenching of an insulator phase. We discuss the importance of impact ionization in the ultrafast response and investigate the interplay between carrier and band dynamics. Our model allows us to compare with recent experiments and identify signatures of carrier multiplication in typical electronic distribution curves as measured by time-resolved photoemission spectroscopy. We also investigate the influence of the shape of the bands on the carrier multiplication.