Thermal conductivity in the diatomic Toda lattice

The diatomic Toda lattice, a linear chain with exponential interaction and alternating masses, is coupled to different heat baths at the two ends. The non-integrability of the system leads to a quasi-ergodic behaviour. It is shown numerically that a stationary linear temperature gradient is supported by the chain. The conductivity coefficient kappa depends on the mass ratio and the temperature of the heat baths, but not on the chain length. The theoretical values for kappa compare reasonably well with experimental results in BN and MgO.