Dresden 2020 – wissenschaftliches Programm
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 14: TEM-based Nanoanalysis and Microstructure of thin films (joint session KFM/CPP)
KFM 14.1: Vortrag
Donnerstag, 19. März 2020, 14:10–14:30, HSZ 301
The effect of dynamical scattering in ferroelectrics on the measurements of internal electric fields by momentum-resolvedSTEM — •Achim Strauch1,2, Andreas Rosenauer3, Andrei Sokolov4, Evgeny Tsymbal4, and Knut Müller-Caspary1,2 — 1Forschungszentrum Jülich — 2RWTH Aachen University — 3IFP Universität Bremen — 4University of Nebraska-Lincoln
Ferroelectric tunnel junctions (FTJs) are one focus of next-generation memories. With these non-volatile memories, the energy consumption can be reduced. Devices with BaTiO3 tunnel junctions cannot be reversibly polarised at ferroelectric thickness below approximately 3 nm [1].
For investigations, a STEM method would be desirable to map the ferroelectric domain structure in ferroelectric nanofilms exploiting the recently accessible four-dimensional data sets from momentum-resolved STEM [2].
In this contribution, we address the impact of systematic errors arising from dynamical scattering, violated inversion symmetry, sample tilt, and redistributions of electrons due to chemical bonding in a simulation study accompanied by experiments on BaTiO3 and PbZrxTi1−xO3.
The effects of dynamical scattering can lead, depending on thickness, to a systematic error [3] in the order of the expected unit-cell averaged electric fields.
Finally the influence of surfaces charges will be discussed.
[1] Garcia et al., Nature Comm. 5, 4289 (2014)
[2] K. Müller et al., Nature Commun. 5, 5653 (2014)
[3] K. Müller et al., Phys. Rev. Lett. 122 (2019)