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Low-temperature thermal rectification by tailoring isotope distributions

We combine first-principles electronic structure calculated thermal conductivity data with a numerical solution of the one-dimensional heat equation to show that an asymmetric distribution of impurity scattering, if suitably designed, yields the conditions for a low-temperature thermal rectification. This happens as a result of the differences in the peaks of the temperature dependence of the thermal conductivity. We demonstrate the effectiveness of the method by probing the thermal rectification rendered by a silicon slab with a steplike position-dependent isotopic composition. The same conclusions are obtained by using experimentally measured values of the thermal conductivity of Si samples with different isotope distributions.