A Cu-based Cu8−xGe(S, Te)6 argyrodite: its widespan cubic-phase region and ultralow lattice thermal conductivity

This work discloses a newly-discovered Cu8−xGe(S, Te)6 argyrodite stabilizing in a high-symmetry cubic phase in the entire low-to-mid temperature region (250-700 K). Partially substituting the sulfur with tellurium increases the configuration entropy, enabling the Cu8−xGe(S, Te)6 as a promising mid-entropy thermoelectric (TE) alloy with ultralow thermal conductivity. © 2023 The Royal Society of Chemistry.