Temperature dependent anharmonic lattice dynamics

We have developed a thorough and accurate method of determining anharmonic properties in solids, the temperature dependent effective potential technique (TDEP). It is based on ab initio molecular dynamics followed by a mapping onto a model Hamiltonian that describes the lattice dynamics. The effective Hamiltonian contains implicit temperature dependence, electron phonon coupling and renormalized anharmonicity to arbitrary order, making it suitable for strongly anharmonic systems. We show excellent results for a host of thermoelectric materials (PbTe, SnTe, Bi$_2$Te$_3$, FeSi, ScN), reproducing temperature dependent phonon spectra, thermal conductivity, and phonon self energies.