Regensburg 2022 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 16: Poster Monday: Ultrafast Processes 1
O 16.12: Poster
Montag, 5. September 2022, 18:00–20:00, P4
Investigations of polarons in hematite α-Fe2O3(1-102) by means of nc-AFM and KMC — •Jesús Redondo1,2, Vít Gabriel1, Giada Franceschi3, Igor Sokolović3, Dominik Wrana1, Florian Kraushofer3, Erik Rheinfrank3, Michele Riva3, Gareth S. Parkinson3, Michael Schmid3, Ulrike Diebold3, Pavel Kocán1, and Martin Setvin1,3 — 1Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic — 2Faculty of Chemistry, University of the Basque Country, San Sebastián, Spain — 3Institute of Applied Physics, Vienna University of Technology, Vienna, Austria
Polarons are known to strongly influence the catalytic activity and the electronic, magnetic, and structural properties of transition metal oxides and halide perovskites. The study of polaron formation and dynamics is fundamental to understanding the actual mechanisms and yields of catalytic reactions in these materials. A new method for the investigation of electron and hole polarons is demonstrated. Charge carriers are injected with the AFM/STM tip into the surface of natural, Ti- and Ni-doped α-Fe2O3(1-102). The injected charges form a cloud of electrons or holes trapped in the lattice. This cloud expands due to electrostatic interactions and thermally activated polaron hopping. Controlled annealing of the sample and characterization by Kelvin probe force microscopy (KPFM) provides information on polaron dynamics; these results are compared to kinetic Monte Carlo (KMC) simulations and the dependence of the polaron hopping activation energy on the doping is shown.