SurfaceScience21 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 72: Mini-Symposium: Coherent band structure engineering with light II
O 72.2: Vortrag
Mittwoch, 3. März 2021, 14:00–14:15, R2
Ultrafast spin-dependent band structure renormalization of a molecular/2D semiconductor heterostructure by the formation of interlayer excitons — •Benito Arnoldi1, Sebastian Hedwig1, Sara Zachritz2, Oliver L.A. Monti2,3, Martin Aeschlimann1, and Benjamin Stadtmüller1 — 1Department of Physics, University of Kaiserslautern, Erwin-Schroedinger-Strasse 46, Kaiserslautern 67663, Germany — 2Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States — 3Department of Physics, University of Arizona, Tucson, Arizona 85721, United States
Engineering the spin-dependent band structure of atomically thin materials with ultra-short light pulses offers the intriguing possibility to control spin and charge carrier functionalities on smallest length and fastest time-scales. Here, we explore the transient band structure dynamics of a heterostructure between C60 and WSe2 after optical excitation with fs light pulses. The ultrafast charge carrier dynamics of the interface is investigated by time-, spin- and angle-resolved photoemission spectroscopy. Resonant optical excitation of the molecular layer instantaneously results in the formation of excitons within the C60 layer. These excitons transform within 200 fs into interlayer excitons, which are trapped at the heterostructure interface for 14 ps. Most interestingly, the formation of the interlayer excitons coincides with a transient spin-dependent renormalization of the valence band structure of WSe2. This transient spin texture modification is attributed to the charge transfer character to the interlayer excitons at the interface.