Phonon anharmonicity, lifetimes, and thermal transport in CH3NH3PbI3 from many-body perturbation theory

Lattice vibrations in CH$_3$NH$_3$PbI$_3$ are strongly interacting, with\ndouble well instabilities present at the Brillouin zone boundary. Analysis\nwithin a first-principles lattice dynamics framework reveals anharmonic\npotentials with short phonon quasi-particle lifetimes and mean-free paths. The\nphonon behaviour is distinct from the inorganic semiconductors GaAs and CdTe\nwhere three-phonon interaction strengths are three orders of magnitude smaller.\nThe implications for the applications of hybrid halide perovskites arising from\nthermal conductivity, band-gap deformation, and charge-carrier scattering\nthrough electron-phonon coupling, are presented.\n