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Thursday, August 14 • 14:30 - 16:30
Quantum Hall Effects III

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14:30-15:00

Invited: Ulf Gennser
Heat Currents & Their Quantum Limit in Electronic Channels
Co-authors: François Parmentier, Anne Anthore, Antonella Cavanna, Yong Jin, Frédéric Pierre

Heat current measurements have recently attracted a large interest because of their importance for understanding edge state transport and low-level energy excitations in the integer and fractional quantum Hall regimes [1, 2]. At a very fundamental level quantum mechanics predicts of a universal limit to the heat flow across a single channel, independent of the type of particle carrying the heat. However, experimentally, this has only been demonstrated for phonons. We report on the quantitative measurement of this limit for Fermi particles across a single electronic channel tailored in a two-dimensional electron gas, using noise thermometry. The demonstrated agreement between the experiment and theoretical value of the heat flow limit - within 10 % - establishes experimentally this basic building block of quantum thermal transport [3]. The investigation opens a pathway to the nanoscale and coherent control of heat currents.

[1] C. Altimiras, H. Le Sueur, U. Gennser, A. Anthore, A. Cavanna, D. Mailly, and F. Pierre, "Chargeless heat transport in the fractional quantum Hall regime," Phys. Rev. Lett. 109, 026803 (2012).
[2] V. Venkatachalam, et al., "Local thermometry of neutral modes on the quantum Hall edge," Nature Physics 8, 676 (2012); A. Bid, et al., "Observation of neutral modes in the quantum Hall regime," Nature 466, 585 (2010).
[3] S. Jezouin, F. D. Parmentier, A. Anthore, U. Gennser, A. Cavanna, Y. Jin, and F. Pierre, "Quantum Limit of Heat Flow Across a Single Electronic Channel," Science 342, 601 (2013).

15:00-15:15
Oral: Toshimasa Fujisawa
Non-Equilibrium Heating between Counter-Propagating Quantum Hall Edge Channels
Co-authors: Kazuhisa Washio, Ryo Nakazawa, Masayuki Hashisaka, Koji Muraki

15:15-15:30
Oral: Robin J. Nicholas
Role of Disorder in the Temperature-Dependent Magneto-Transport of Graphene near the Dirac Point
Co-authors: Jian Huang, Jack Alexander-Webber, JT Janssen, Alexander Tzalenchuk, Vladimir Antonov, Thomas Yager, Samuel Lara-Avila, Sergey Kubatkin, Rositza Yakimova, Robin Nicholas

15:30-15:45
Oral: Francois Sfigakis
Evidence for an Anisotropic Phase at 5/2 Filling in High Mobility GaAs Holes with Electric Field Sensitive Orientation
Co-authors: Andrew Croxall, Nii Dodoo-Amoo, Inti Sodemann, Allan MacDonald, Ian Farrer, Harvey Beere, David Ritchie

15:45-16:00
Oral: Tristan Meunier
Using a Two-Electron Spin Qubit to Detect Electron Flying Above the Fermi Sea
Co-authors: Romain Thalineau, Christopher Bauerle, Andreas Wieck

16:00-16:15
Oral: Tomoaki Ota
Cross Correlation Measurement of Repartitioned Noise in a Quantum Hall Edge Channel
Co-authors: Masayuki Hashisaka, Koji Muraki, Toshimasa Fujisawa

16:15-16:30
Oral: Nikola Pascher
Imaging the Conductance of Integer & Fractional Quantum Hall Edge States
Co-authors: Clemens Rössler, Thomas Ihn, Klaus Ensslin, Christian Reichl, Werner Wegscheider 

Session Chairs
MO

Milan Orlita

Laboratoire National des Champs Magnétiques Intenses, CNRS
Dr. Milan Orlita received his B.S. and Ph.D. (2006) from the Charles University in Prague, Czech Republic. Currently, he is a postdoctoral research fellow at Laboratoire National des Champs Magnetiques Intenses, CNRS, Grenoble, France. He is also affiliated with the Academy of Sciences of the Czech Republic. He has published extensively on optical measurements of solid-state systems, especially the graphene layers in recent years.

Speakers
UG

Ulf Gennser

Laboratoire de Photonique et de Nanastructures, CNRS
Ulf Gennser recieved his Ph.D. in 1992 from Columbia University (New York), working on resoant tunneling in SiGe heterostructures. He is currently the group leader of « Physics and Technology of Nanostructures » at the Laboratoire de Photonique et de Nanostructures, CNRS, France, and responsible for the molecular beam epitaxy of high mobility electronic systems. His main interest is in mesoscopic physics, and currently, among other... Read More →


Thursday August 14, 2014 14:30 - 16:30
Room 18AB

Attendees (6)