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TT: Fachverband Tiefe Temperaturen

TT 6: Topological Semimetals

TT 6.9: Talk

Monday, March 27, 2023, 11:45–12:00, HSZ 304

The anomalous photo-Nernst effect in a Dirac semimetal — •Maanwinder Partap Singh^1,2, Jonas Kiemle^1,2, Waldemar Schmunk^1,2, Alexander Holleitner^1,2, and Christoph Kastl^1,2 — ¹Walter Schottky Institut, Technical University of Munich, Am Coulombwall 4a, 85748 Garching, Germany. — ²Munich Center of Quantum Science and Technology (MCQST), Schellingstr. 4, 80799 Munich, Germany.

The 3D Dirac semimetal HfTe₅ is a model system to study unconventional Hall transport phenomena, such as quasi quantized and anomalous Hall efects, in the limit of very low charge carrier densities. Here, we report on anomalous photocurrents in HfTe₅, which are intimately linked to the anomalous Hall and the related Nernst conductivities. As the dominant mechanism of photocurrent generation, we establish a, hitherto hidden, anomalous photo-Nernst effect of 3D Dirac electrons. The anomalous photo-Nernst effect manifests itself as a long-range, photoresponse along the crystal edge arising from a Shockley-Ramo type response and the local symmetry breaking at the edge. The observed temperature and density dependences of the anomalous photo-Nernst currents are consistent with a dominating intrinsic Berry curvature mechanism.