No abstract

We theoretically study the heat generation induced by the electric current in a quantum dot coupled to a normal and a superconducting lead with weak dot-leads coupling. We find that the heat generation presents quite different properties from the current and can be controlled by the gate voltage, bias and temperature. At zero temperature, there are many ideal regions for device operation with large electric current and small heat generation. Interestingly, at high temperature, the heat generation can become negative in the regions where the phononassisted Andreev tunneling and phonon-assisted direct tunneling with absorbing a phonon can occur. This means such a device can serve as a refrigerator.

Spin-filtering effect in the transport through a single-molecule magnet Mn 12 bridged between metallic electrodes