Phonon-mediated back-action of a charge readout on a double quantum dot.
Quantum point contacts are in use as an on-chip capacitative readout for the charge state of quantum dot systems. Here we investigate experimentally the back-action of quantum point contacts (QPCs) on a nearby double quantum dot (DQD). Driving current through a QPC influences the DQD state and leads to a measurable current flow in the DQD circuit with no bias voltage applied. The responsible mechanism is an indirect back-action process due to ohmic heating of the phonon bath. The system behaves like a thermoelectric engine, where a temperature gradient between the phonon bath and the electronic bath generates work observable as a measurable current flowing through the DQD.
Gasser
U
U
Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland. szerer@phys.ethz.ch
Gustavsson
S
S
Küng
B
B
Ensslin
K
K
Ihn
T
T