Surface structure and reactivity of
multi-component oxides at the atomic scale

Subproject P02

Multi-component metal oxides exhibit a plethora of stoichiometry-dependent structural phases at the surface, even if the composition of the bulk is kept the same. The long-term objective of P02 is to unravel the relationship between surface electronic and geometric structure and reactivity, to ultimately tune these materials for energy-related reactions such as the ORR. The project applies the surface science approach. We will grow well-defined, epitaxial perovskite thin films of LSFO and LSMO in a UHV-based PLD/surface science apparatus under tight control of the surface stoichiometry in the first project period. We will determine the coordinates of surface atoms quantitatively using LEED-IV in close collaboration with theoretical groups.

Theoretical models will also help with interpreting atomically-resolved ncAFM/STM images. These images give direct insights into the behavior of polarons in these complex materials and show how adsorbates such as O2, H2O, CO, and CO2 interact with electronic and structural defects. XPS, TPD, and FTIR of these well-defined systems will deliver desorption energies, vibrational frequencies, and spectral fingerprints. These experimental data on well-defined systems will build a bridge when tested under ‘realistic’ environments at high pressure/temperature and in aqueous solutions. They will also serve to validate ML-based theory approaches.

Ulrike Diebold
PI

Expertise

Our expertise is experimental surface science. We operate a total of seven ultrahigh-vacuum (UHV) chambers, which contain virtually all main experimental surface science techniques, as well as an (electro-)chemistry lab.

All chambers are equipped with facilities for sample preparation (sputtering/annealing/gas dosing), as well as various growth techniques (e-beam evaporators, Knudsen cells, UHV-compatible sputter deposition, pulsed laser deposition (PLD)).

Analysis techniques used in our research include:

  • Scanning Tunneling Microscopy (STM) (in UHV 4K – 300 K, electrochemical STM)
  • Atomic Force Microscopy (AFM): UHV-based (q+ sensor) and in the ambient (cantilever-based)
  • Low-Energy Electron Diffraction (LEED)
  • Reflection High Energy Diffraction (RHEED)
  • X-ray Photoelectron Spectroscopy (XPS)
  • Ultraviolet Photoelectron Spectroscopy (UPS)
  • Auger Electron Spectroscopy (AES)
  • Low-energy He+ ion scattering (LEIS)
  • Thermal Programmed Desorption Spectroscopy (TPD)

Of particular use for TACO is our combined Pulsed-Laser Deposition/Surface Science setup shown on the right-hand side. It allows the growth of multi-component metal oxides and the investigations of surface properties within the same UHV setup.

Team

Ulrike Diebold
PI

Michele Riva
co-PI

Michael Schmid
co-PI

Alexander Michael Imre
PhD Student

Erik Rheinfrank
PhD Student

Michael Brunthaler
Master Student

Florian Dörr
Master Student

Publications

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2021

α-β phase transition of zirconium predicted by on-the-fly machine-learned force field

Liu, Peitao; Verdi, Carla; Karsai, Ferenc; Kresse, Georg

α-β phase transition of zirconium predicted by on-the-fly machine-learned force field Journal Article

In: Physical Review Materials, 5 (5), pp. 053804, 2021.

Abstract | Links | BibTeX | Tags: P03, pre-TACO

First-principles hydration free energies of oxygenated species at water–platinum interfaces

Jinnouchi, Ryosuke; Karsai, Ferenc; Verdi, Carla; Kresse, Georg

First-principles hydration free energies of oxygenated species at water–platinum interfaces Journal Article

In: The Journal of Chemical Physics, 154 (9), pp. 094107, 2021.

Abstract | Links | BibTeX | Tags: P03, pre-TACO

2020

On-the-Fly Active Learning of Interatomic Potentials for Large-Scale Atomistic Simulations

Jinnouchi, Ryosuke; Miwa, Kazutoshi; Karsai, Ferenc; Kresse, Georg; Asahi, Ryoji

On-the-Fly Active Learning of Interatomic Potentials for Large-Scale Atomistic Simulations Journal Article

In: The Journal of Physical Chemistry Letters, 11 (17), pp. 6946–6955, 2020.

Abstract | Links | BibTeX | Tags: P03, pre-TACO

2017

Polaron-Driven Surface Reconstructions

Reticcioli, Michele; Setvin, Martin; Hao, Xianfeng; Flauger, Peter; Kresse, Georg; Schmid, Michael; Diebold, Ulrike; Franchini, Cesare

Polaron-Driven Surface Reconstructions Journal Article

In: Physical Review X, 7 (3), pp. 031053, 2017.

Abstract | Links | BibTeX | Tags: P02, P03, P07, pre-TACO