Accelerated discovery of a large family of quaternary chalcogenides with very low lattice thermal conductivity

Abstract

The development of efficient thermal energy management devices such as thermoelectrics and barrier coatings often relies on compounds having low lattice thermal conductivity (κl). Here, we present the computational discovery of a large family of 628 thermodynamically stable quaternary chalcogenides, AMM′Q3 (A = alkali/alkaline earth/post-transition metals; M/M′ = transition metals, lanthanides; Q = chalcogens) using high-throughput density functional theory (DFT) calculations. We validate the presence of low κl in these materials by calculating κl of several predicted stable compounds using the Peierls–Boltzmann transport equation. Our analysis reveals that the low κl originates from the presence of either a strong lattice anharmonicity that enhances the phonon-scatterings or rattler cations that lead to multiple scattering channels in their crystal structures. Our thermoelectric calculations indicate that some of the predicted semiconductors may possess high energy conversion efficiency with their figure-of-merits exceeding 1 near 600 K. Our predictions suggest experimental research opportunities in the synthesis and characterization of these stable, low κl compounds.

Quaternary Selenides EuLnCuSe3: Synthesis, Structures, Properties and In Silico Studies

“…Selenides of the rhombic system EuLnCuSe 3 (Ln = La-Lu, Sc, Y) with the band gap of 0.82-1.09 eV were also predicted [32]. Quaternary selenides EuLnCuSe 3 are also indirectly predicted by the existence of tertiary selenides CuLnSe 2 [18,48,49].…”

“…Quaternary selenides, comprising copper and rare earth elements, are of particular interest due to a variety of different combinations of cations that enable the design of the structural type and band gap, as well as electrical and optical characteristics [1][2][3]8,[22][23][24][25][26][27][28][29][30][31][32][33]. Recent theoretical studies well predict thermoelectric properties of the copper-derived quaternary selenides [32,34,35], which are one of the promising alternatives to traditional thermoelectric materials. Notably, copper-containing chalcogenides are more abundant in the Earth's crust and are relatively cheap in comparison to the bismuth-and leadderivatives [36].…”

“…Additionally, the magnetic and optical properties of these compounds have also been described [1,3,8,30]. Quaternary selenides have a high energy conversion efficiency with a figure of merit higher than unity at 600 K [32]. Due to a 4f-5d transition in the Eu 2+ ion, incorporation of this ion into the compound yields in a narrower band gap [9], than, e.g., 1.96 eV obtained for BaGdCuSe 3 [3].…”

“…For a series of thermodynamically stable quaternary chalcogenides ALnCuSe 3 (A = Sr, Ba, Pb, Eu), quantum mechanical calculations revealed a very low thermal conductivity of the lattice due to its strong anharmonicity, which enhances phonon scattering [32]. Compounds with low thermal conductivity can be used as high-performance thermoelectrics in thermal barrier coatings and thermal data-storage devices [32,[44][45][46][47].…”

“…The former compounds should form in the CuLnSe 2 -EuS section of the EuS-Ln 2 Se 3 -Cu 2 S ternary system analogously to the chalcogenides of a similar composition [38][39][40][41][50][51][52][53][54][55][56][57][58][59]. Three structural types were predicted for EuLnCuSe 3 , namely KZrCuSe 3 (Ln = Nd-Lu, Y), BaLaCuS 3 (Ln = La-Pr) and NaCuTiS 3 for EuScCuSe 3 [32]. This contradicts the data obtained for the synthesized Eu +2 Eu +3 Cu +1 Se −2 3 , for which the structural type of Eu 2 CuS 3 with the cell parameters a = 10.773 (7) Å, b = 4.134(3) Å, c = 13.466(9) Å was established [31].…”