High-throughput study of Cu-Fe-S minerals as new thermoelectric materials

Large-scale production of thermoelectrics devices requires the design of novel materials that not only exhibit high performance but also are low cost and earth-abundant. In this context sulfide minerals are a largely unexplored field. Here we investigate the electronic and vibrational properties for 6 minerals in the copper iron sulfide family including Mawsonite (Cu_{6}Fe_{2}SnS_{8}), Mooihoekite (Cu_{9}Fe_{9}S_{16}) and Nukundamite (Cu_{3.38}Fe_{0.62}S_{4}). Typically, such materials have complex crystal structures with large unit cells, where interstitial atoms in the tetrahedral sites can be partially occupied. Electronic and thermal transport results are obtained using the recently developed PAOFLOW package (www.aflow.org/paoflow) integrated in AFLOWπ high-throughput framework (http://aflowlib.org/src/aflowpi/), including improved electronic structure using the new ACBN0 functional. Our results show that Cu-Fe-S minerals have specific vibrational features that indicate low thermal conductivity and good electronic properties making them promising candidates in thermoelectric applications for low-grade waste heat recovery.