We calculate zT as a function of electron concentrations and temperatures (Figure ) from the computed charge transport properties and the experimental κ L reported in Ref. 10 for undoped, polycrystalline Y 2 Te 3 . We chose to use the experimental κ L values to allow direct comparison with experiments and also to provide a realistic prediction of zT . Since the experimental κ L values in Ref. 10 are reported at temperatures different from the ones we report in Figure , we fit the temperature dependence assuming κ L is limited by Umklapp scattering: