Nonlinear Peltier effect and thermoconductance in nanowires

A theoretical analysis of thermal transport in nanowires, in field-free conditions and under influence of applied magnetic fields, is presented. It is shown that in the nonlinear regime (finite applied voltage) new peaks in the Peltier coefficient appear leading to violation of Onsager's relation between the Peltier and thermopower coefficients. Oscillations of the peltier coefficient in a magnetic field are demonstrated. The thermoconductance has a steplike quantized structure similar to the electroconductance and it exhibits deviations from the Wiedmann-Franz law. The strong dependence of the thermoconductance on the applied magnetic field leads to the possibility of magnetic blockade of thermal transport in wires with a small number of conducting channels. Possible control of thermal transport in nanowires through external parameters, that is applied through finite voltages and magnetic fields, is discussed. [S0163-1829(99)04140-5].