Lone-pair-driven suppression of out-of-plane phonon transport and excellent near-room-temperature thermoelectric performance in layered hexagonal γ-GeSe.
Intrinsically low lattice thermal conductivity is essential for high-performance thermoelectrics. Recently, the hexagonal GeSe polymorph has been reported to host stereochemically active lone-pair electron states (LPEs), offering a promising platform for exploring ultralow thermal transport. However, the specific role...