The second most probable structure (𝑃 𝑛 = 0.2), on the other hand, has a much smaller 𝜅 ave of 0.62 W m -1 K -1 , which is lower than Bi2Te3. Since the other 19 of the 21 structures in the alloy model would also show some level of chalcogen disorder compared to the ideal arrangement, we would expect these to have a 𝜅 latt closer to the second structure, which would in turn bring the complete weighted sum closer to the ~10 % smaller 𝜅 latt relative to Bi2Te3 measured in Ref. .