High-throughput Discovery of a Promising Thermoelectric Heteroanionic Materials Family

Heteroanionic materials, or mixed-anion materials, have interesting properties due to the presence of multiple anions, but are much fewer experimentally reported comparing to single-anion compounds. Here, we demonstrate how high-throughput DFT calculations can accelerate the discovery of heteroanionic compounds created from homoanionic materials. CsCuLa₂Se₄ and CsCu₃Gd₂Se₅, two typical compounds in ACuLnQ (1124 and 1325, A=Cs, Rb; Ln=rare earth; Q=S, Se, Te) materials family, were discovered years ago. Using the Open Quantum Materials Database (OQMD) platform, our high-throughput study finds many unreported yet stable compounds for both 1124 and 1325 ACuLnQ materials. The thermal transport property calculations demonstrate that this material family is a good candidate as a thermoelectric material due to ultra-low thermal conductivity. Further, we find three different Wyckoff positions of anion sites in both 1124 and 1325 structures and create hypothetical mixed-anion materials by replacing all anions on one Wyckoff position with some other anion. High-throughput calculations predict 61 new stable and over 200 metastable mixed-anion compounds, largely expanding the phase space of ACuLnQQ’ materials family.