Regensburg 2022 – scientific programme
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O: Fachverband Oberflächenphysik
O 57: Poster Wednesday: Electronic Structure
O 57.5: Poster
Wednesday, September 7, 2022, 18:00–20:00, P4
Spontaneous Charge Localization on Polar Surfaces — •Michele Reticcioli1, Zhichang Wang2,3, Zdenek Jakub2, Igor Sokolovic2, Matthias Meier1,2, Gareth S. Parkinson2, Michael Schmid2, Dominik Wrana4, Lynn A. Boatner5, Ulrike Diebold2, Martin Setvin2,4, and Cesare Franchini1,6 — 1Faculty of Physics and Center for Computational Materials Science, University of Vienna, Austria — 2Institute of Applied Physics, TU Wien, Vienna, Austria — 3State Key Laboratory for Physical Chemistry of Solid Surfaces, Xiamen University, China — 4Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic — 5Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, USA — 6University of Bologna, Italy
Excess charge on polar surfaces of ionic compounds is commonly described by the two-dimensional electron gas (2DEG) model, a homogeneous distribution of charge confined in a few atomic layers. Conversely, our density functional theory calculations and scanning-probe microscopy measurements on KTaO3(001) show spontaneous localization of the excess charge in the form of polarons, bipolarons and charge density waves. These electronic reconstructions form on the defect-free surface, and alter the material properties and functionalities to different degrees. Controlling the degree of charge ordering could be of great benefit for a wide range of applications: in our study, we analyze the impact on the surface reactivity by considering the interaction with CO molecules.