Berlin 2018 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 89: Oxide and Insulator Surfaces: Structure, Epitaxy and Growth I

O 89.5: Vortrag

Donnerstag, 15. März 2018, 11:30–11:45, MA 041

Relaxation effects in VO₂/TiO₂(001) films — •Jon-Olaf Krisponeit¹, Simon Fischer¹, Sven Esser^2,3, Vasily Moshnyaga³, Jan Ingo Flege¹, and Jens Falta¹ — ¹Institut für Festkörperphysik, Universität Bremen, 28359 Bremen, Germany — ²Experimentalphysik VI, Universität Augsburg, 86159 Augsburg, Germany — ³1. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany

Bulk vanadium dioxide (VO₂) exhibits a metal-insulator transition at 340 K. On TiO₂(001) substrates, the tensile in-plane stress can be utilized for a reduction of T_MI to room temperature due to the compression of the out-of-plane rutile c-axis of VO₂.

Aiming for such epitaxial VO₂/TiO₂(001) films under high coherent strain, potential relaxation effects annihilating stress and/or modifying surfaces and interfaces should be taken into account. Films were prepared by reactive molecular beam epitaxy and metal-organic aerosol deposition. Structural and morphological properties were analyzed by low-energy electron microscopy and diffraction as well as scanning probe microscopy. We discuss three distinct relaxation effects: (i) surface facetting, (ii) the formation of a misfit dislocation network, and (iii) topographic buckling and even crack patterns for thick films.

Support by the Institutional Strategy of the University of Bremen funded by the German Excellence Initiative is acknowledged.