  The Peltier effect is the reverse phenomenon of the Seebeck effect, and has
been observed experimentally in nanoscale junctions. However, despite its
promising applications in local cooling of nanoelectronic devices, the role of
strong electron correlations on such a phenomenon is still unclear. Here, by
analyzing the thermoelectric properties of quantum impurity systems out of
equilibrium, we unveil the essential role of electron-electron interactions and
quantum resonant states in Peltier cooling, leading to the prediction of the
Kondo cooling phenomenon. The existence of such Kondo cooling is validated by a
reverse heat current and a lowered local temperature in a model junction. The
discovery of this unconventional Peltier cooling offers a new approach toward
nano-refrigeration, and highlights the unique role of strong electron
correlations in nonequilibrium quantum systems.
