Thermoelectric Properties of Novel Semimetals: A Case Study of YbMnSb₂

Abstract

The emerging class of topological materials provides a platform to engineer exotic electronic structures for a variety of applications. As complex band structures and Fermi surfaces can directly benefit thermoelectric performance it is important to identify the role of featured topological bands in thermoelectrics particularly when there are coexisting classic regular bands. In this work, the contribution of Dirac bands to thermoelectric performance and their ability to concurrently achieve large thermopower and low resistivity in novel semimetals is investigated. By examining the YbMnSb2 nodal line semimetal as an example, the Dirac bands appear to provide a low resistivity along the direction in which they are highly dispersive. Moreover, because of the regular‐band‐provided density of states, a large Seebeck coefficient over 160 µV K−1 at 300 K is achieved in both directions, which is very high for a semimetal with high carrier concentration. The combined highly dispersive Dirac and regular bands lead to ten times increase in power factor, reaching a value of 2.1 mW m−1 K−2 at 300 K. The present work highlights the potential of such novel semimetals for unusual electronic transport properties and guides strategies towards high thermoelectric performance.

Giant anomalous Nernst signal in the antiferromagnet YbMnBi2

“…22 )—are reported to be magnetic topological materials with a canted spin structure; they are therefore able to hold a non-zero Berry curvature 23 , 24 . Moreover, the bands contributed by pnictides are highly dispersive 25 , which can provide a low resistivity, especially compared with that of ferromagnets.…”

Magnetic structure of the topological semimetal YbMnSb2

“…A particular interest is to identify materials in which the topology of the electronic states can be controlled by their magnetic order [6][7][8][9][10]. Recently, the antiferromagnetic (AFM) metal YbMnSb 2 has been proposed as one such material, with the property that the topology of the bands near the Fermi energy (E F ) depends on the specific spin configuration on the Mn magnetic sublattice [11][12][13][14][15][16].…”

Trendbericht Festkörperchemie 2022

“…Die Gruppen von Felser und Snyder haben herausgearbeitet, welchen Nutzen die komplexe Bandstruktur dieser Verbindungsklasse (topologische Halbmetalle mit (4 4 )-Strukturmotiv) hat. 50) Dazu ordneten sie die thermoelektrischen Eigenschaften von YbMnSb 2 den vorherrschenden Merkmalen der Bandstruktur zu. Während die steilen Dirac-Bänder des Halbmetalls eine hohe elektrische Leitfähigkeit erlauben, beeinflussen reguläre Bänder die Transporteigenschaften, was zu einem hohen Seebeck-Koeffizienten führt.…”