(color online) (a) Schematic diagrams illustrating various electron spin and phonon scatterings in quaternary magnetic nanocrystals and (b) comparison of the zT among Cu₂XSnS₄ nanocrystals.^[61] Reproduced from Ref. [61] with permission from the Royal Society of Chemistry, (c) electronic and (d) phonon band structure for Cu₂CoSnS₄.^[67] Reproduced from Ref. [67] with permission from Elsevier.