Berlin 2024 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 40: 2D Materials and Heterostructures: Magnetic Properties
HL 40.8: Vortrag
Donnerstag, 21. März 2024, 11:45–12:00, EW 201
Optoelectronic investigation of Berry curvature dipole induced non-linear anomalous thermal Hall effect in type-II Weyl Semimetal WTe2 — •Ernst Knöckl1, 2 and Christoph Kastl1, 2 — 1Walter Schottky Institut, Munich, Germany — 2TU Munich, Germany
The Berry curvature forms the foundation for the topological classification of band structures. Importantly,
it also impacts a material’s (opto-)electronic properties, for example by introducing an anomalous transversal correction to the group velocity of
charge carriers. Generally, symmetry constraints often preclude the observation of such effects, and only few, low-symmetry materials directly show relevant topological
transport properties. In particular, few-layer WTe2 has been shown to exhibit a nonlinear anomalous Hall effect [1] due to its low crystal symmetry and its strong
Berry curvature dipole (BCD). We discuss the requirements for optically detecting a so far elusive thermal analogue of this effect, which is the socalled nonlinear anomalous thermal Hall effect (NLATHE). In principle, the NLATHE allows for experimentally accessing the first derivative of the BCD with respect to the chemical potential [2]. We present first results obtained on few-layer WTe2 integrated into on-chip thermal circuits made from silicon nitride membranes.
[1] Sodemann, I., et al.
Physical Review Letters 115.21 (2015): 216806
[2] Zeng, C., et al. Physical Review Research 2.3 (2020): 032066
Keywords: Nonlinear Optoelectronics; Anomalous Hall effect; Berry curvature dipole; Weyl semimetals