Regensburg 2022 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 7: (Quantum) Transport Properties

HL 7.2: Vortrag

Montag, 5. September 2022, 15:15–15:30, H31

Anomalous photo-Nernst currents in HfTe₅ — •Waldemar Schmunk, Maanwinder Singh, Alexander Holleitner, and Christoph Kastl — Walter Schottky Institut

Recently, strong evidence of a quasi-quantized 3D quantum Hall effect in non-magnetic semimetals HfTe₅ and ZrTe₅ has been reported by various groups. Plateau-like features in the Hall conductivity of HfTe₅ and ZrTe₅ point towards unconventional Hall physics in these 3D semimetals. Additionally, in high-density HfTe₅ crystals, an anomalous, but non-hysteretic, Hall conductivity has been reported as well, which points to a non-zero Berry curvature. Here, we present photocurrent measurements of thin HfTe₅ films in an external magnetic field. We find a localized edge photo response with opposite polarity at opposite edges. We interpret these edge photocurrents in terms of an anomalous Nernst current arising from the local excitation, the symmetry breaking at the edges, and the anomalous Hall conductivity. Such local photocurrents open the possibility to image anomalous Hall responses and possible related edge state physics in layered quantum materials.