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Thermoelectricity : From Classical to Quantum Engines
Thermoelectric effects result from the interference of electrical current and heat flow in various materials. This interaction, characterized by a coupling parameter called thermopower, allows direct conversion of heat to electricity ; conversely cooling may be obtained by application of a voltage across a thermoelectric material. Almost 200 years after the first discoveries in thermoelectrics by Seebeck in 1821 there is again a very active period in observing thermoelectric phenomena, including the development of materials and their application into devices. From a thermodynamic point of view thermoelectricity is often presented as the illustration of the Onsager theory of linear out of equilibrium response. We will discuss some recent developments of thermoelectric materials and engines, and show how this approach allows to consider some new effects, especially when considering unsteady responses. In particular, we will show how these phenomena extend the classical description to the quantum description, in particular when considering the discrete description, nicely given by the so-called Feynman Ratchet.