Regensburg 2019 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

O: Fachverband Oberflächenphysik

O 95: Semiconductor Substrates: Metallic Nanowires

O 95.3: Vortrag

Freitag, 5. April 2019, 11:00–11:15, H14

Excited state mapping and ultrafast population dynamics in In/Si(111) nanowires probed by trARPES — •Chris W. Nicholson1, Michele Puppin1, Andreas Lücke2, Wolf Gero Schmitt2, Laurenz Rettig1, Ralph Ernstorfer1, and Martin Wolf11Fritz Haber Institute, Berlin — 2University of Paderborn

Ultrafast electronic structure probes allow detailed insights into the microscopic processes underlying photo-induced phase transitions, as recently exemplified by the time- and angle-resolved photoemission spectroscopy (trARPES) study of the model (8x2) to (4x1) structural transition in In/Si(111) nanowires [1].

In this talk, I will address two further aspects of the electronic structure dynamics as probed by our trARPES setup utilizing a 22 eV laser at 500 kHz. The first is the extension of the band-mapping concept to states above the Fermi level, which allows a rigorous benchmarking of band structure calculations in this system. The second is an energy and momentum resolved analysis of the population dynamics during the phase transition. A comparison with a simulated band structure based on a transient electronic temperature finds impressive agreement, supporting the high electronic temperature extracted in the surface layer following excitation. These results are compared to those obtained with femtosecond electron diffraction [2] and imply a non-thermal phonon population of the surface In atoms and suggest a bottleneck for cooling of optical phonons.

[1] Nicholson et al. Science 362, 821 (2018)

[2] Frigge et al. Struct. Dyn. 5, 025101 (2018)

100% | Mobil-Ansicht | English Version | Kontakt/Impressum/Datenschutz
DPG-Physik > DPG-Verhandlungen > 2019 > Regensburg