Cooling effect of thermal bias on a current-carrying nanodevice

• Electrons are driven by both electric bias voltage and thermal bias.
• Heat in a QD can be conducted efficiently away via electron–phonon interaction.
• Current through a QD maximizes where the heat generation is zero.

We investigate the heat generation in a quantum dot (QD) coupled to two normal leads with different temperatures. It is found that heat in the QD can be conducted efficiently away through electron–phonon interaction in the QD when the QD is coupled stronger to colder lead than to the hotter one. As temperature of the colder lead is close to zero, the current through the QD peaks at the very QD level position, where the heat generation is zero, which helps to keep the stability of a working nanodevice. Then an ideal condition for nanodevice operation can be found.