LAUSR

Abstract Argyrodite compounds have recently attracted increasing attention as promising thermoelectric materials because of the intrinsic ultralow lattice thermal conductivity. Such a low lattice thermal conductivity, coming from weakly bonded cations, low sound velocity, and a large number of atoms in the primitive cell, frequently leads to promising thermoelectric performance, particularly in Ag8SnSe6 and Ag9Ga(Al)Se6. Motivated by the commonness of argyrodite compounds in bonding and crystallography features, this work focuses on a new member of argyrodite, Ag9GaS6, for its potential thermoelectric applications. The carrier concentration can be tuned through Se/S substitution for enhancing the electronic performance. In combination with an intrinsically low lattice thermal conductivity of ∼0.25 Wm−1K−1 in the entire temperature range, Ag9GaS6-based materials show a thermoelectric figure of merit zT of ∼0.6, enriching sulfide argyrodites as thermoelectrics.