First-principles investigations of phonon anharmonicity and electronic instability in thermoelectric SnSe*

The promising thermoelectric material SnSe exhibits ultra-low and strongly anisotropic thermal conductivity. By combining first-principles calculations and inelastic neutron scattering measurements, we have investigated the phonon dispersions and phonon scattering mechanisms, and probed the origin of the large anharmonicity in SnSe.\footnote{C.W. Li*, J. Hong*, A.F. May, D. Bansal, S. Chi, T. Hong, G. Ehlers, and O. Delaire, “Orbitally driven giant phonon anharmonicity in SnSe”, Nature Physics, (2015)} We will discuss the connection between the phonon properties and the high-temperature structural phase transition, and how the electronic structure leads to large anharmonic phonon interactions in SnSe. The present results provide a microscopic picture connecting electronic structure and phonon anharmonicity in SnSe, which could help design materials with ultralow thermal conductivity.