ICT2014 Abstracts

Concerns over element toxicity and the low abundance of some elemental components such as tellurium and cobalt have compelled us to study earth-abundant materials for thermoelectricity.  Guided by density functional theory calculations of lattice dynamics and electronic structure calculations, we have identified the tetrahedrite family of minerals as potential high performance thermoelectric materials.  Importantly, the tetrahedrites comprise the most widespread sulfosalts on Earth. An unusual band structure gives rise to large Seebeck coefficient over a wide range of composition, spanning those compositions of tetrahedrite that occur in nature.  Meanwhile, large anharmonicity drives the lattice thermal conductivity down to near minimum values.  As a result, tetrahedrites can possess dimensionless figures of merit exceeding unity at 400C, comparable or even exceeding that of some of the best synthetic thermoelectric materials in this temperature range. We also show that samples synthesized using natural mineral tetrahedrite as a source material possess similar values of figure of merit.  The results suggest a new paradigm for thermoelectric material development – the use of natural minerals directly as sources for highly efficient thermoelectric materials.