The NS2 (NanoStructures at the NanoSecond timescale) group is broadly interested electronic transport in quantum mesoscopic systems and especially in the dynamics of such systems. We are presently investigating, among other things, the dynamics of SNS or SFS junctions (S=superconductor, N=normal metal, F=ferromagnet), non-Gaussian high frequency quantum noise, (non-equilibrium) spin dynamics and spin-dependent thermoelectric effects in superconductors, as well as unconventional superconducting proximity effects in micro-magnetic systems.
NS2 is part of the Laboratoire de Physique des Solides (LPS, Solid State Laboratory), a loboratory under the joint management of the Centre National de Recherche Scientifique (CNRS) and the Université Paris-Sud, housed on the campus of the latter in Orsay (about 30km south-west of Paris on the Saclay plateau).
With 200 faculty (not including CNRS research staff in jointly-managed laboratories), the Université Paris-Sud's Physics Department is one of the world's largest. Several of the department's twenty-one laboratories focus in part or entirely on condensed matter research including: the LPS, the Institut d'Electronique Fondamontale, the Centre de Sciences Nucléaires et de Sciences de la Matière, and the Unité Mixte de Physique CNRS/Thales.
We are always happy to talk to bright and motivated students interested in internships, PhD positions or postdocs. Please feel free to contact us.
Quantum statistics of surface plasmons excited by tunnel junctions. / Statistique quantique des plasmons de surface excités par une jonction tunnel More details.
Spin and Charge Injection into a Mesoscopic Superconductor using Acoustically Excited Ferromagnetic Resonances / Injection de charges et spins dans un supraconducteur mésoscopique grâce à l'excitation acoustique de la résonance férromagnétique. More details.
September 2016 Marko Kuzmanović and Gianluca Aiello have joined us as PhD students.
June 2016 Nikhita Baladari, from the Birla Institute of Technology and Science, has joined us as an intern.
May 2016 Faten Ben Chaabane, Alexander Noddings (an undergraduate from the University of Illinois at Urbana-Champaign) and Mohamed Ouerfelli have joined us as interns.
March 2016 Marko Kuzmanović, a masters student at the University of Belgrade, has returned to the group as an intern.
February 2016 Bi Yi Wu, a PhD student in Chi Te Liang's group, is visiting us from the National Taiwan University for six months.
October 2015 Mathieu Féchant has started his PhD in the group.
September 2015 Alexis Morvan has started his PhD in the group and Gianluca Aiello from the University of Trento (Italy) has joined us as an intern.
July 2015 The work realized by Julien Basset and his ex-colleagues at ETH Zurich was awarded through a publication in Physical Review Letters. In this work Julien and co-authors report the first experimental observation of microwave emission from hybridized states in a semiconductor charge qubit. On-line Paper
June 2015 Pierre Chevalier and Clément Leroy have joined us as interns.
May 2015 Charles Rigoudy has joined us as an intern.
April 2015 We have observed the spin resonance of quasiparticles in superconducting aluminium. Unlike in normal metals, the spin coherence and spin imbalance relaxation times (respectively T2 and T1) diverge, pointing to different mechanisms for decoherence and relaxation. Our results suggest that spin coherence is limited by Elliott-Yafet spin-orbit scattering. Article
February 2015 Freek Massee has joined the group as a postodoc. Freek comes to us from Seamus Davis's group at Cornell.
January 2015 Cyril Vaneph has joined the group as a PhD student.
Alexis Morvan and Mathieu Féchant have joined us as interns.
October 2014 Jérôme Estève has joined the group. Jérôme is a CNRS researcher previously attached to the Laboratoire Kastler Brossel in Paris.
Marko Kuzmanović, from the University of Belgrade, has joined us as an intern.
September 2014 Julien Basset, a new faculty hire in Physics at the Université Paris-Sud has joined the group. Julien was a postdoc at the ETH Zurich with Andreas Walraff and Klaus Ensslin.
Maximilian Weideneder, from the University of Regensburg, will be spending the academic year with us as part of his diplomarbeit.
Tom Dvir, from Hadar Steinberg's group at the Hebrew University in Jerusalem, is visiting us and the Mesoscopic Physics group for a few weeks.
August 2014 We have measured the spin (imbalance) lifetime in a superconductor in the frequency domain. This work follows on our recent demonstration of non-equilibrium magnetism in superconductors, in the form of pure spin imbalances. In a nutshell, our measurement is akin to filling a leaky bath from a tap, turned on and off at a regular rhythm, while measuring the time-averaged water level in the bath. Experiment, Theory.
May 2014 Yann Chiffaudel has joined us as an intern. Christoph Strunk is visiting the group.
April 2014 Jordan Bouaziz has joined us as an intern.
January 2014 Tito Williams has joined us as a 'visitor'.
November 2013 The radiation generated by a quantum conductor should be correlated with the electrons crossing it. We have measured the correlation between the fluctuations of the high-frequency electromagnetic power generated by a tunnel junction at very low temperature and the low-frequency voltage fluctuations across it. This quantity corresponds to a third-order correlator of the electromagnetic field. At low-voltage bias, i.e. when the junction emits no radiation into the impedance-matched vacuum connected to it, we observe that the voltage fluctuations of the electric signal generated by the junction has zero third moment. Yet we show by a careful analysis of environmental contributions that the intrinsic third moment of the high-frequency current fluctuations in the junction is given by e2I. arXiv, New Journal of Physics,
October 2013 Pierre Février has started his PhD in the group.
February 2013 We have shown that it is possible to control the shot noise across a tunnel junction using high-frequency 'biharmonic illumination', i.e. voltage excitation at two discrete frequencies. This allows us to control the non-equilibrim electronic distribution function of the reservoirs. arXiv, Physical Review B,
January 2013 Baydir Bouali and Pierre Février have joined us as interns, Edouard Pinsolle as a postdoc.
August 2012 What happens to spin-polarised electrons when they enter a superconductor? Superconductors at equilibrium and at finite temperature contain both paired particles (of opposite spin) in the condensate phase as well as unpaired, spin-randomised quasiparticles. Injecting spin-polarised electrons into a superconductor thus creates both spin and charge imbalances. These must relax when the injection stops, but not necessarily over the same time (or length) scale as spin relaxation requires spin-dependent interactions while charge relaxation does not. We have shown that it is possible to have spin imbalance but not charge imbalance (and vice versa). arXiv, Nature Physics, News and Views