Crystal chemistry in phase change thermoelectrics

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Thermoelectric materials convert thermal in electrical energy and provide the possibility to recover waste heat in industrial processes. However, the underlying crystal chemical influences on thermoelectric transport is still not fully understood. Novel approaches for improved thermoelectric transport focus on the engineering of the band structure to achieve band convergence and high band degeneracy. Just recently, it was shown that a high crystal symmetry leads to a high number in the band degeneracy. The hypothesis of this proposal is based on the current understanding that a more cubic lattice will lead to better thermoelectric transport. Phase change materials exhibit good thermoelectric transport in their cubic high temperature structures and are ideal candidates for understanding the effects of crystal symmetry on the transport. Using crystal chemical approaches the phase changes will be altered, and the structural symmetry controlled. This proposal seeks a better fundamental understanding of how elemental substitution can shift or suppress phase changes and stabilize high temperature crystal structures at lower temperatures. The resulting effect on the thermoelectric transport will be explored.