Berlin 2018 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 101: Correlated Electrons: Other Materials

TT 101.2: Talk

Thursday, March 15, 2018, 15:45–16:00, HFT-FT 101

An optical study of the electrically driven insulator-metal transition in V₂O₃ — •Matthias Lange¹, Dennis Schwebius¹, Stefan Guénon¹, Yoav Kalcheim², Ilya Valmianski², Marcelo Rozenberg², Ivan K. Schuller², Reinhold Kleiner¹, and Dieter Koelle¹ — ¹Physikalisches Institut - Experimentalphysik II and Center for Quantum Science (CQ) in LISA⁺, Universität Tübingen, D-72076 Tübingen — ²Department of Physics and Center for Advanced Nanoscience, University of California - San Diego La Jolla, CA 92093, USA

The strongly correlated oxide V₂O₃ undergoes an insulator-metal transition (IMT) from a low-temperature antiferromagnetic insulating phase to a paramagnetic metallic phase at around 160 K, resulting in a several orders-of-magnitude change in resistivity. We investigated the electrical breakdown of a V₂O₃ thin film, grown by rf-sputtering on a r-cut sapphire substrate, by concomitantly measuring the electrical properties as well as the spatially resolved optical reflectivity. At temperatures near the IMT, the current voltage characteristics show jumps to lower voltages, indicating electrical breakdown of the insulating phase. Whether this electrically driven IMT is electric-field induced or caused by the creation of electro-thermal domains through Joule heating is in focus of recent research. The reflectivity measurement reveals that the breakdown is accompanied by a change in reflectivity, which can be attributed to the formation of spatially confined metallic filaments.

Work at UCSD supported by an MRPI and AFOSR grants.