Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 89: Oxide and Insulator Surfaces: Structure, Epitaxy and Growth I
O 89.4: Vortrag
Donnerstag, 15. März 2018, 11:15–11:30, MA 041
The stability of ultra-thin ZrO2 films on a metallic substrate: a challenge for DFT? — Wernfried Mayr-Schmölzer, Jakub Planer, Tobias Hruby, Florian Mittendorfer, and •Josef Redinger — Institute of Applied Physics and Center for Computational Materials Science, TU Vienna, Wiedner Hauptstrasse 8-10/134, 1040 Vienna, Austria
At first DFT calculations for bulk ZrO2 are performed to assess the accuracy of semi-local, vdW corrected and hybrid functionals as compared to a many-body approach, ACFDT-RPA. Whereas all the functionals reproduce the experimental order of stabilities of known phases, the relative stability of two additionally found meta-stable phases with comparable energies depends on the functional used. For ultra-thin films on metals as grown both on Pt(111) [1] and Rh(111) [2], we investigate the structural stabilities of a suggested tri-layer O-Zr-O film on both substrates. The DFT calculations show that such O-Zr-O tri-layers are quite strained on both metals, but they behave differently on Pt or Rh. Obviously, for Rh the tensile stress can be compensated by O-Rh bonds at the interface while this is not working for Pt. For Pt the stress leads to a heavily corrugated O-Zr-O layer not witnessed in experiment. Even the recently developed most advanced SCAN meta-GGA functional, which matches well with our ACFDT-RPA benchmark for bulk ZrO2, does not cure the problem.
[1] M. Antlanger, et. al., PRB86, 035451 (2012)
[2] P. Lackner and M. Schmid, TU Vienna, work in progress (2017)