Another potential avenue would be to try to optimise the κ κ κ of the rocksalt systems by reducing the group velocities while retaining the strong intrinsic anharmonicity. Experimental studies have demonstrated that solid solutions of Pnma SnS and SnSe can display lower κ κ κ than both endpoints, and our recent modelling suggests this is primarily due to a reduction in the ν ν ν λ , 40 so alloying may be a facile route to achieving this. Another pos-sibility is the "discordant doping" approach demonstrated by Xie et al. where a carefully-selected dopant is incorporated into the lattice at a few at.% to deliberately induce structural distortion and chemical bond strain. Based on the analysis presented here, we would expect this to also lead to a reduction in the group velocities, and to thus be a viable strategy to lower the κ latt of rocksalt-structured chalcogenides.