DQMP Seminar - Monitoring and design of polar states during complex oxide thin film growth

04.06.2019 13:00 – 14:30

In ferroelectric thin films, the polarization state, i. e. orientation and domain architecture, defines
the macroscopic ferroelectric properties such as the switching dynamics. Ferroelectric domain
engineering is in permanent evolution from the epitaxial strain tuning to the chemical control on
interface atomic termination. Technology promising complex polar flux closure or vortices
architecture have been recently demonstrated in ferroelectric heterostructures. However the
mechanism involved in the formation of these complex polar states remains unexplored. The
optical second harmonic generation process is an efficient and non-invasive tool for thin films
ferroic properties probing. Here, we investigate the emergence of the ferroelectric polarization in
ultra-thin ferroelectric and multiferroic films and monitor in situ the optical non-linear response of
the films during the growth. We find that, the ferroelectric critical thickness and domain state can
be addressed in situ during the film deposition. The impact of epitaxial strain, surface termination
and electrostatic environment on the polar state of ultra-thin films and multilayers can now be
explored in real-time, exempt from substrate contribution. Our work provides direct observation
of ferroelectric states during the growth as well as new insights towards further control of
ferroelectric-based heterostructure.

Lieu

Bâtiment: Ecole de Physique

Auditoire Stückelberg

entrée libre