Phonon anharmonicity, lifetimes and thermal transport in   CH$_3$NH$_3$PbI$_3$ from many-body perturbation theory
  Lattice vibrations in CH$_3$NH$_3$PbI$_3$ are strongly interacting, with double well instabilities present at the Brillouin zone boundary. Analysis within a first-principles lattice dynamics framework reveals anharmonic potentials with short phonon quasi-particle lifetimes and mean-free paths. The phonon behaviour is distinct from the inorganic semiconductors GaAs and CdTe where three-phonon interaction strengths are three orders of magnitude smaller. The implications for the applications of hybrid halide perovskites arising from thermal conductivity, band-gap deformation, and charge-carrier scattering through electron-phonon coupling, are presented. 
Lucy D. Whalley, Jonathan M. Skelton, Jarvist M. Frost, Aron Walsh
cond-mat.mtrl-sci