Nonlinear Peltier effect and thermoconductance in nanowires

A theoretical analysis of thermal transport in nanowires, in field-free con ditions and under influence of applied magnetic fields, is presented. It is shown that in the nonlinear regime (finite applied voltage) new peaks in t he Peltier coefficient appear leading to violation of Onsager's relation be tween the Peltier and thermopower coefficients. Oscillations of the peltier coefficient in a magnetic field are demonstrated. The thermoconductance ha s a steplike quantized structure similar to the electroconductance and it e xhibits deviations from the Wiedmann-Franz law. The strong dependence of th e thermoconductance on the applied magnetic field leads to the possibility of magnetic blockade of thermal transport in wires with a small number of c onducting channels. Possible control of thermal transport in nanowires thro ugh external parameters, that is applied through finite voltages and magnet ic fields, is discussed. [S0163-1829(99)04140-5].