Heat Transport Measurements in Electronic Quantum Channels

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• Dr Ulf Gennser, CNRS - Laboratory of Photonics and Nanostructures, France
• Wednesday 19 March 2014, 14:15-15:15
• Mott Seminar Room, Cavendish Laboratory, Department of Physics.

If you have a question about this talk, please contact Teri Bartlett.

A number of recent experiments have demonstrated that heat transport studies can reveal new insights into the physics of mesoscopic systems. In particular, they have revealed novel properties of edge state transport and low-level energy excitations in quantum Hall systems, where otherwise the robust quantization of Hall currents limits the amount of information that can be obtained from charge transport alone. In this talk, I will review some of these results, including those obtained in our group.

Spurred on by these findings, we have been able to significantly improve our heat current measurements. This has made it possible to measure the thermal conductance quantum Gq for Fermi particles across a single electronic channel. In contrast to charge transport, Gq is predicted to be independent of the type of particles carrying the heat. Such universality, combined with the relationship between heat and information, signals a general limit on information transfer. It was previously measured for Bose particles, across the sixteen vibrational modes of narrow bridges. Using noise thermometry and quantum point contacts in a 2D electron gas, we demonstrated an experimental agreement with the predicted value of Gq for electrons at an accuracy better than 10%. This establishes experimentally this basic building block of quantum thermal transport and opens access to new experiments involving the quantum manipulation of heat.

This talk is part of the Semiconductor Physics Group Seminars series.

This talk is included in these lists:

• All Cavendish Laboratory Seminars
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• ME Seminar
• Mott Seminar Room, Cavendish Laboratory, Department of Physics
• Neurons, Fake News, DNA and your iPhone: The Mathematics of Information
• School of Physical Sciences
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• Thin Film Magnetic Talks

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