Heat conduction in 2d harmonic lattices with on-site potential

Abstract

We discuss heat conduction in 2d lattices, the first example of a class of 2d harmonic crystals subject to on-site anharmonic potentials. In general, they do not show up linear thermal gradient in contrast to their Id counterparts. Inclusion of specific nonlinearity, however, leads to conductivity which diverges logarithmically with system size. The variation of thermal conductivity (K) with temperature and dissipation enables us to identify a dynamical contribution over and above the thermodynamic factor allowed by the transition state theory as K= Kdynamic × K thermodynamic and to distinguish the regimes of energy diffusion and spatial diffusion in the nonequilibrium stationary state in thermal conduction. © EDP Sciences.