Both our predictions and experiments are nevertheless considerably larger than the κ latt of flagship materials such as Bi 2 Te 3 and SnSe, for which we calculated lattice thermal conductivities of 0.875 and 1.58 W m -1 K -1 in previous studies using similar methodology (the experimental values are 1.28/1.37 and 0.5-1.4 W m -1 K -1 ). However, the measurements in Ref. , and experiments on high-entropy perovskite oxides, demonstrate that the κ latt can be significantly reduced by controlling the chemical composition.