Regensburg 2025 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 10: Topological Semimetals
TT 10.10: Talk
Monday, March 17, 2025, 17:30–17:45, H36
Anomalous photo-Nernst effect and impact of disorder in HfTe5 films — Maanwinder Singh1,2, Tobias Meng3, and •Christoph Kastl1,2 — 1Walter-Schottky-Institute, Technical Unversity of Munich, Germany — 2Munich Center for Quantum Science and Technology — 3Institute of Theoretical Physics and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, Germany
We discuss optoelectronic transport in thin films of HfTe5, which is a non-magnetic, weakly gapped semimetal at the border of a weak to strong topological insulator transition. We find that focused photoexcitation results in strong a transversal response at finite magnetic field, which we describe in terms of a Berry curvature driven anomalous photo-Nernst effect of three-dimensional massive Dirac fermions [1]. We further use Raman microscopy to reveal significant microscale disorder and strain in contacted films, which has important implications for the interpretation of transport experiments in HfTe5 due to the sensitivity of its electronic structure to external strain [2].
[1] Singh et al., Adv. Phys. Res. 3, 2300099 (2024).
[2] Singh et al., ACS Nano 18, 18327 (2024).
Keywords: Berry curvature; anomalous Hall; photocurrent; disorder