Electronic structure as a guide in screening for potential thermoelectrics: Demonstration for half-Heusler compounds

Abstract

We adopt a high throughput search strategy that begins with electronic structure features to screen a set of half-Heusler compounds for thermoelectric performance. This is motivated by the contradictory electrical transport requirements, specifically high electrical conductivity, σ and high thermopower, S, for obtaining high figure of merit, ZT. We use an electronic fitness function that measures the extent to which a specific band structure decouples σ and S for this purpose. We then perform detailed, more costly, calculations of thermal conductivity and electrical properties for those compounds that have a high electronic fitness. This provides an efficient method for identifying promising compounds from a set of candidates. We apply this to a set of 75 previously studied half-Heusler compounds. The approach identifies several compounds as having potential as thermoelectric materials. Importantly, these include not only some previously identified candidates, but also some other compounds that had not been identified previously using other screening methods.

Thermoelectric property enhancement by merging bands in NbFeSb-based half-Heusler mixtures

“…As the elements in the HH system change, the band gap can be varied within the range of 0-4 eV. [13][14][15] Thus, 18-e HH compounds with an adjustable band gap (the semiconductor behavior) are suitable for thermoelectric applications. More importantly, the unique electronic structures of HH compounds lead to high electrical properties.…”

Thermoelectric Transport Parameters of p‐Type RuVAs and RuNbAs Heusler Alloys

“…[ 40 ] The ZT value of the RuNbAs compound can be improved by p‐type doping. In this view, Feng et al [ 40 ] have shown that ZT reaches the value of 0.9 at 1000 K for a doping of 17.75 × 10 19 cm −3 . The ZT of RuVAs material increases with increasing temperature until 0.47 at 900 K and then decreases gradually.…”

“…ZT of the RuNbAs material has a maximum value of 0.62 at 1000 K. At this temperature, the half‐Heusler compounds often exhibit good performance. [ 40 ] The ZT value of the RuNbAs compound can be improved by p‐type doping. In this view, Feng et al [ 40 ] have shown that ZT reaches the value of 0.9 at 1000 K for a doping of 17.75 × 10 19 cm −3 .…”

Binary and Ternary Colloidal Cu‐Sn‐Te Nanocrystals for Thermoelectric Thin Films

“…The TE electronic fitness function EFF was as described by Xing et al [65] and measured the extent to which a band structure incorporated features that decouple conductivity and thermopower to the benefit of TE performance. [66] The ceramic average Seebeck is the conductivity weighted average, S cer = (σ x S x + σS y + σ z S z )/(σ x + σ y + σ z ). The direction average EFF is the average of the EFF over the three directions.…”