HEAT-CONDUCTION IN DISORDERED ANHARMONIC SYSTEMS

The heat transport of (2D) disordered dielectric model systems in the high-temperature regime is studied in two respects. Firstly, Lye find that the heat conductivity due to hopping of localized phonons increas es linearly with the temperature up to a ''saturated'' value, which em erges at certain strengths of the coupling with the extended phonons. Secondly, third- or fourth-order anharmonicity is shown to lower or en hance the conductivity, respectively, which can be understood by weake ning or strengthening of the stiffness of the bonds in the system.