Theory of thermoelectricity in Mg3Sb2 with an energy- and temperature-dependent relaxation time

Roberta Farris; Maria Barbara Maccioni; Alessio Filippetti; Vincenzo Fiorentini

doi:10.1088/1361-648X/aaf364

Theory of thermoelectricity in Mg₃Sb₂ with an energy- and temperature-dependent relaxation time

J Phys Condens Matter. 2019 Feb 13;31(6):065702. doi: 10.1088/1361-648X/aaf364. Epub 2018 Nov 23.

Authors

Roberta Farris¹, Maria Barbara Maccioni, Alessio Filippetti, Vincenzo Fiorentini

Affiliation

¹ Department of Physics at University of Cagliari, and CNR-IOM, UOS Cagliari, Cittadella Universitaria, I-09042 Monserrato (CA), Italy.

PMID: 30524117
DOI: 10.1088/1361-648X/aaf364

Abstract

We study the electronic transport coefficients and the thermoelectric figure of merit ZT in [Formula: see text]-doped Mg₃Sb₂ based on density-functional electronic structure and Bloch-Boltzmann transport theory with an energy- and temperature-dependent relaxation time. Both the lattice and electronic thermal conductivities affect the final ZT significantly, hence we include the lattice thermal conductivity calculated ab initio. Where applicable, our results are in good agreement with existing experiments, thanks to the treatment of lattice thermal conductivity and the improved description of electronic scattering. ZT increases monotonically in our [Formula: see text] range (300-700 K), reaching a value of 1.6 at 700 K; it peaks as a function of doping at about [Formula: see text] cm^-3. At this doping, ZT [Formula: see text] 1 for [Formula: see text] K.