Enhanced Thermoelectric Effect by Attractive Interaction
The thermoelectric efficiency of solid state materials is encapsulated in the so called "figure of merit" ZT. Optimal ZT, in linear response theory, is obtained by enhancing the Seebeck coefficient and the conductance and reducing the thermal conductivities through the device.
The figure shows lower/upper bounds on ZT for several gate voltages for a quantum dot with attractive local Coulomb interaction. Since quantum dots are tunable, optimal ZT values are obtained at any temperature by suitable choice of a gate voltage. This "negative-U" mechanism for enhancing the thermopower and ZT of quantum dots demonstrates how novel correlation effects may help to improve thermoelectric efficiency at the nanoscale with possible applications to energy efficiency and cooling in quantum devices.
S. Andergassen, T. A. Costi, V. Zlatic, Phys. Rev. B 84, 241107 (2011)