Notably, the anomalous Hall and anomalous Nernst signals are not at the same energy, indicating that by shifting the Fermi level, different signals may be detectable. The magnetism (introduced by X or Y atoms) enhance spin-orbital coupling to facilitate band crossings around the Fermi level, which results in a large Berry curvature that may lead to large anomalous Hall and Nernst signals. (a) Band structure with Weyl point around the Fermi level (with crystal structure in the inset), (b) Berry curvature, (c) anomalous Hall conductivity and (d) anomalous Nernst conductivity. will be studied to enhance the thermoelectric performance of the materials.įigure 1 The relationship between anomalous transport properties and band structures in magnetic Heusler Weyl semimetals from theoretical calculations. Manipulation of the Fermi level, chemical composition, anisotropy of the sample, magnetic field strength etc. Single and polycrystalline samples will be synthesized, and their electrical, thermal and magnetotransport properties will be measured. New materials for synthesis will mainly be chosen from computational predictions that show large ANE. Berry curvature) and intriguing fundamental physics in Weyl semimetals. For example, the magnetic Heusler family is a very good system for the research: (1) by breaking time-reversal symmetry, magnetic Heusler Weyl semimetals can have large ANE, which is promising for the breakthroughs of thermoelectrics (2) therefore these Heusler compounds can contribute to better understanding of the complex band structure ( e.g. More importantly, the band inversion from the large spin-orbit interaction in Weyl semimetals gives rise to transport anomalies, such as anomalous Hall effect (AHE) and anomalous Nernst effect (ANE) ( Figure 1). However, in the Nernst thermopower configuration (field induced transverse thermopower), the partial thermopower is increased by utilizing two types of charge carriers in semimetals. On the other hand, in classic thermoelectric materials, one type of charge carrier is used. Computational studies have predicted that magnetic field can induce a nonsaturating thermopower in topological materials due to their unique band structure. However, little is known about the thermoelectric properties of these materials. Recently, topological materials have attracted a lot of research interest due to their exotic properties induced by the topological band structure. My research, funded by the Alexander von Humboldt foundation, focuses on experimentally uncovering the interplay of thermoelectrics and topology in Weyl semimetals.
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