QuEnG Seminar - Heat Transport and Thermo-power in a Single-Quantum-Dot Transistor

on the February 6, 2019

At 3:00pm
As part of the QuEnG Seminar, we are pleased to welcome Hervé Courtois, who is professor at Université Grenoble Alpes. He does research in Thermal transport in quantum devices, Charge transport in quantum dots, Out-of-equilibrium superconductivity..
We report on the thermo-electricity and the heat transport in a tunnel-contacted and gate-tunable individual single-quantum dot junction, fabricated using the electromigration technique. A pair of hybrid Josephson junctions inserted in the vicinity of the junction enable us to raise and/or monitor the electronic temperature of one of the two leads, the other one being well thermalized to the bath. Using this set-up, we could study the heat dissipation in the quantum-dot junction as a function of both the gate potential and the bias. The data highlights the gate-sensitivity of the thermal conductance through the quantum dot.

In the Kondo regime, we report the first measurement of the Seebeck coefficient. This fundamental thermoelectric parameter is obtained by directly monitoring the magnitude of the voltage induced in response to a temperature difference across the junction, while keeping a zero net tunneling current through the device. Striking sign changes of the Seebeck coefficient are induced by varying the temperature, depending on the spin configuration in the quantum dot. The comparison with numerical renormalization group (NRG) calculations demonstrates that the tunneling density of states is generically asymmetric around the Fermi level in the leads, both in the cotunneling and Kondo regimes.

If you don't usually have acces to the Institut Néel main site (CNRS campus, Presqu'île) send an email to Agostino APRA before 12:00pm on 5th of February so that your entry passes can be sent to you.

Published on February 3, 2019

Practical informations


Centre National de la Recherche Scientifique (CNRS)
Room K223, Rémy Lemaire 
25 Avenue des Martyrs, 38000 Grenoble