2.1.3 Thomson Effect

Beside the Seebeck and Peltier effect, Thomson (later Lord Kelvin) observed the third thermoelectric effect. Assuming a homogeneous conductor with a temperature gradient applied, carriers traversing the temperature gradient gain or release energy depending on their relative direction to the temperature gradient. Applying local energy balance, the energy change of the traversing carriers is absorbed or released as heat, respectively. The total Thomson heat absorbed or released along one rod is given by

$$J_\ensuremath{\mathrm{Thomson}}^\ensuremath{\mathrm{q}} = \int_{\... ...nsuremath{T_{\mathrm{H}}}} \ensuremath{\chi}(\ensuremath{T}) J \d\ensuremath{T}$$ (2.8)

where $\ensuremath{\chi}(\ensuremath{T})$ depicts the temperature dependent Thomson coefficient. Thomson and Seebeck coefficient are connected by the second Kelvin relation

$$\ensuremath{\chi}= \ensuremath{T}\frac{\d\ensuremath{\alpha}}{\d\ensuremath{T}}$$ (2.9)

as carried out in the following section.

M. Wagner: Simulation of Thermoelectric Devices