Regensburg 2019 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 4: Topological insulators and spin-dependent transport phenomena

MA 4.3: Vortrag

Montag, 1. April 2019, 10:00–10:15, H52

Characterization of topological band structure features away from the Fermi level via the anomalous Nernst effect — •Jonathan Noky, Johannes Gooth, Claudia Felser, and Yan Sun — Max Planck Institute for Chemical Physics of Solids, Dresden, Deutschland

Resolving the structure of energy bands in transport experiments is a major challenge in condensed matter physics and material science. Sometimes, however, when traditional electrical measurements only provide very small signals, it has been proven beneficial to employ thermoelectric measurements which are sensitive to the first derivative of the electrical property with respect to energy, rather than to its value itself. Due to the large interest in topological effects these days, it is important to identify a similar concept for detecting the Berry curvature (BC) in a band structure. The BC can be created by different mechanisms like Weyl points or the gapping of nodal lines due to symmetry breaking. Nowadays, the common way to access the BC directly via measurements is the anomalous Hall effect, but the corresponding signal can be too small to be detected when the topological features of the band structure lie too far off the Fermi level.

We investigate the strong BC due to nodal line gappings in regular Heusler compounds for different positions of the Fermi level. From this we derive a way to resolve topological band structure features which are elusive to see in anomalous Hall measurements utilizing the anomalous Nernst effect.