Electronic structure and thermoelectric properties of CoAsSb with post-DFT approaches

Abstract

We study the electronic structure and thermoelectric properties of recently synthesized CoAsSb. The calculated bandgap becomes more accurate for increasingly-complex electronic structure methods: generalized gradient approximation, hybrid functionals, self-consistent linearized quasiparticle GW method (LQSGW), and LQSGW with simplified vertex corrections. By equating the bandgaps of each method from a rigid shift of the bands, we evaluate the contributions made to thermoelectric properties beyond the bandgap. In doing so, we evaluate the efficacy of a common-practice: a rigid shift applied to less-costly electronic structure methods in order to gain some accuracy of the more-costly methods. We find that while the shift made the Seebeck coefficients much closer to one another than from the original electronic structures, there remain differences in the Goldsmid-Sharp (thermoelectric) bandgap between the methods and from the intended electronic bandgap. Additionally, some lasting differences in temperature dependence remain between the methods.

Order–Disorder Transition in Inorganic Clathrates Controls Electrical Transport Properties

“…The band gaps for all compositions were individually corrected by using a rigid (“scissors”) shift. In particular, each of these was set equal to the value obtained by performing DFT calculations for the same structure using the mBJ functional, which gives band gaps in better agreement with experiment. , Still, our tests reveal that this correction leaves the electrical conductivity largely unaffected, while the Seebeck coefficient is only slightly enhanced at temperatures above 700 K (see Figure S7 and Supporting Information Note S5).…”

Prototypical many-body signatures in transport properties of semiconductors

“…This estimate works decently for both n− and p-type semiconductors [86], although deviations of the order of a factor of two are not uncommon. The relation is used as a coarse analysis tool [87][88][89] in simulations and experiments and even as a descriptor in high-throughput materials discovery studies [90]. Eq.…”