First principles study on the thermoelectric performance of CaAl$_2$Si$_2$-type Zintl phase compounds

Hidetomo Usui; Kazuhiko Kuroki

doi:10.7566/JPSJ.89.124707

paper

First principles study on the thermoelectric performance of CaAl $_{2}$ Si $_{2}$ -type Zintl phase compounds

arXiv:2008.10917 · doi:10.7566/JPSJ.89.124707

Abstract

We investigate the thermoelectric properties of CaAl $_{2}$ Si $_{2}$ -type Zintl phase compounds $A B_{2} X_{2}$ ( $A$ = Mg, Ca, Sr, Ba, $B$ = Mg, Zn, Cd, and $X$ = P, As, Sb) using first principles band calculations within the Boltzmann transport theory assuming the constant relaxation time approximation. We introduce the effective degree of valley degeneracy $n_{T E}$ to focus on the relationship between the thermoelectric properties and the multivalley character of the electronic band structure around the Fermi level. We also introduce a quantity $γ_{T E}$ , which takes into account $n_{T E}$ and anisotropy of the valley structure, and it is found that $γ_{T E}$ enables us to well understand the overall trend of the material dependence of the power factor. We finally suggest promising thermoelectric materials, e.g. BaMg $_{2}$ P $_{2}$ for PF $\sim 20 μ$ W/cmK $^{2}$ and $Z T > 0.2$ at 300K and SrZn $_{2}$ As $_{2}$ for PF $\sim 35 μ$ W/cmK $^{2}$ and $Z T > 0.35$ at 300K assuming a relaxation time of 10 fs and a lattice thermal conductivity value of 2 W/mK.

29 pages, 11 figures

First principles study on the thermoelectric performance of CaAl $_{2}$ Si $_{2}$ -type Zintl phase compounds

Abstract

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First principles study on the thermoelectric performance of CaAl2​Si2​-type Zintl phase compounds

Abstract

References in corpus (4)

Cited by in corpus (3)

First principles study on the thermoelectric performance of CaAl $_{2}$ Si $_{2}$ -type Zintl phase compounds