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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 79: Nanostructured Surfaces and Thin Films I: 1D and 2D Networks (joint session O/CPP)

CPP 79.1: Vortrag

Mittwoch, 18. März 2020, 15:00–15:15, WIL B321

Imaging the phase transition in thin film VO₂ microstructures — •Jan O. Schunck^1,2, Florian Döring³, Benedikt Rösner³, Jens Buck⁴, Sanjoy Mahatha¹, Moritz Hoesch¹, Christian Schüßler-Langeheine⁵, Adrian Petraru⁶, Hermann Kohlstedt⁶, Kai Rossnagel^1,4, Christian David³, and Martin Beye^1,2 — ¹Deutsches Elektronen-Synchrotron DESY, Hamburg — ²Physics Department, Universität Hamburg — ³Paul Scherrer Institut, Villigen-PSI, Switzerland — ⁴Institut für Experimentelle und Angewandte Physik, CAU Kiel — ⁵Helmholtz-Zentrum Berlin — ⁶Nanoelektronik, Techn. Fakultät, CAU Kiel

Vanadium dioxide (VO₂) is an intruiging compound, since upon heating it exhibits an insulator-to-metal transition (IMT) at a critical temperature T_c of around 340 K, which is characterised by a decrease in resistivity of several orders of magnitude. On a microscopic level, the phase transition is accompanied by a rearrangement of the crystal structure as well as electronic bands around the Fermi level and proceeds in a percolative manner, meaning that both phases coexist over a temperature range of several K around T_c.

Here, we present results of an experiment which combines X-ray spectroscopic methods for electronic structure analysis with imaging capabilities of a few micrometers spatial resolution. Studying electronic structure changes during the thermally driven IMT in a pulsed laser deposition-grown and microstructured VO₂ thin film, shows that T_c differs by around 2 K between the edges and centres of VO₂ squares with an edge length of 30 µm.