In our research group (abbreviated NS2) we study electronic transport in quantum matter systems and especially the dynamics of such systems. Our current research includes 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, atomic scale shot-noise 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 laboratory under the joint management of the Centre National de Recherche Scientifique (CNRS) and the Université Paris Saclay. We are located on the Saclay plateau in Orsay, approximately 30km south-west of Paris.

We are always happy to talk to bright and motivated students interested in internships, PhD positions or postdocs. Some ideas for internships or projects can be found here. Please feel free to contact us.


Research

People

Publications



M2 internships proposal for the season 2020-2021:

Inelastic tunneling and light emission:

Light emission by inelastic tunneling in a metallic tunnel junction have recently emerged as plasmonic alternative to integrated photonics combining the advantages of photonics (high speed and large bandwidth) with those of electronics (extreme miniaturization and integration). Our recent work [1] allows us to understanding the interplay between quantum electronic transport (quantum description of electromagnetic coupling) and photon emission processes (elastic vs inelastic tunneling). For the time being, this source is not an efficient light emitter and it is difficult to characterize the generated photon state. Indeed, due to its low brightness, it is difficult to perform correlation measurements. The source is a biased metal-insulator-metal tunnel junction. Such structure has been known to emit radiations for a long time, but has been neglected because of its low electron-to-photons conversion efficiency (about 10-5 ph/e). However, a carefully designed plasmonic nano-antenna may allowed us to increase the conversion efficiency by two orders of magnitude [2] by focusing on surface plasmons (about 10-3 pl/e) in a nano-antenna. SPP are still detected through their photons leakage in a Kretschmann configuration [3] where the plasmon-to-photon conversion rate is limited by the Joule dissipation. It would therefore be better to directly detect surface plasmons emitted by the junction in order to deal with a full "plasmonic platform". The realization of an integrated "plasmonic platform" involving source and detector of plasmons would therefore be a very useful tool involved in the development of new quantum sensors. The internship will be devoted to the development of a kinetic inductance surface plasmon polariton detector (KISPPD). It involves nano-fabrication (electronic lithography, thin film deposition to realize an LC circuit, see figure), microwave measurement at low temperature and optical excitation of surface plasmon polaritons. In parallel with the work on the development of the KISPPD, we plan to continue the work already begun on the correlation electron-plasmons. The candidate will use samples already made and will have to improve the detection system already used.

(a) Schematic of the detecting board. The NbN inductor is isolated from the metallic layer with a thin layer of SiO and allows a local detection of propagating SPP in a metallic film (red) .(b) Simulated transmission of the LC resonator in a hanger configuration.

[1] Février, P. & Gabelli, J. Tunneling time probed by quantum shot noise. Nat. Commun. 9, 4940 (2018).

[2] Zhang, C. Excitation électrique de plasmons polaritons de surface par effet tunnel inélastique avec des nanoantennes résonnantes. http://www.theses.fr (2019).

[3] Kretschmann, E. & Raether, H. Radiative Decay of Non Radiative Surface Plasmons Excited by Light. Z. Naturforsch. 23a, (1968).
Contacts: Julien Gabelli (julien.gabelli@u-psud.fr)

Phone number: +33 1 69 15 53 65

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Dynamics and correlations of magnetic impurities on a superconductor:

Hybrid magnet-superconducting systems (i.e. arrays of magnetic impurities on a superconducting substrate) have attracted widespread interest for their high potential in topological quantum computation. Nano-fabrication techniques combined with local probe microscopies have recently revealed the emergence of zero-energy modes on ferromagnetic chains [1,2] and ferromagnetic nano-islands on s-wave superconductors [3,4]. The next main challenge is to control these (alleged Majorana) modes, and understanding their coherence and entanglement properties. The building block of the hybrid systems is the single magnetic impurity, whose spin can be screened by electrons with opposite spin that hop on and off the impurity ( Kondo effect). For partial spin screening, the magnetic impurity acts as a pair-breaking potential leading to Bogoliubov excitations with electron-hole parity named Yu-Shiba-Rusinov (YSR) states. Although the time-averaged properties of these in-gap states (spatial extent, orbital dependence, spin polarization...) are well understood from scanning probe studies, little is known about the dynamics of transport into them. This is because typical scanning probes have a limited bandwidth, and therefore cannot access time dependent processes. In this project, we will use our recently developed finite frequency scanning tunnelling microscope [5, 6] to quantify the correlations and charge of the tunneling processes into YSR states. Secondly, we will extend the YSR studies to more complicated systems in order to shed the light on the emergence of Majorana Fermions. For that, we will build up defect-free magnetic chains, magnetic islands or any other combination of well-defined-geometric structures, such as T-shape structures for quantum computing, by atom manipulation techniques. As a master student, you will first become familiar with the scanning tunnelling microscopy (STM) setup, characterise the atomically sharp tip and calibrate the finite frequency circuitry through shot-noise measurements on standard metals such as platinum. Afterwards, you will investigate the properties of magnetic impurities on superconductors grown in-situ under ultra-high vacuum (UHV) conditions by conventional and shot-noise STM measurements.

[1] S. Nadj-Perge et al., Science 346, 6209 (2014)
[2] H. Kim et al., Science Adv. 4, eaar5251 (2018)
[3] G. Menard et al., Nat. Comm. 8, 2040 (2017)
[4] A. Palacio-Morales et al., Science Adv. 5, aav6600 (2019)
[5] F. Massee, Rev. Sci. Instrum. 89, 093708 (2018)
[6] F. Massee et al., Nat. Comm. 10, 544 (2019)
Contacts: Alexandra Palacio-Morales (alexandra.palacio-morales@universite-paris-saclay.fr), Freek Massee (freek.massee@universite-paris-saclay.fr)

Phone number: +33 1 69 15 80 11

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Time reversal breaking in a transmon molecule:

The realization of artificial lattices with broken time reversal symmetry is a very active field of research in condensed matter, ultracold atoms and photonics. The long term objective of our team is to realize such lattices for microwave photons using the tools of circuit QED. A first step in this direction is the study of a molecule formed by a ring of three transmons as shown in the figure (a). In the absence of external fields, the first two excited states of the molecule, which correspond to two states with opposite angular momentum, are degenerate. But, as shown in the figure (b), applying both an electric and a magnetic field to the molecule lifts the degeneracy and breaks time reversal symmetry [1]. The aim of this internship will be to confirm these calculations and to design a circuit to observe this effect. We will then fabricate the circuit and confirm experimentally that the first two excited states carry orbital angular momentum.

(a) Scheme of the transmon molecule formed by a ring of three Josephson junctions. (b) Preliminary calculation of the molecule spectrum as a function of the magnetic flux through the ring in the presence of electric field (Vg ≠ 0). The dashed line shows a possible working point where the degeneracy between the first two excited states (orange and green lines) is lifted. The goal of the internship will be to prove theoretically and experimentally that these two states carry opposite angular momentum.

[1] J. Koch, A. Houck, K. Le Hur and S.M. Girvin, Phys. Rev. A 82, 043811 (2010).
Contacts: Jérôme Estève (jerome.esteve@u-psud.fr), Julien Gabelli (julien.gabelli@u-psud.fr)

Phone number: +33 1 69 15 53 65

February 2021
The paper by Freek Massee and collaborators on high speed atomic rotor in Bi2Se3 has appeared into ACS Nano.

November 2020
Ognjen Stanisavljevic has joined the group as a phd student to work on single microwave photon detection.

August 2020
The paper by Marko Kuzmanovic and collaborators on spin energy modes in mesoscopic superconductors has appeared into Nature communications.

August 2020
A news and views article has appeared regarding our published work on the dynamics of strongly driven Josephson junctions.

February 2020
A news and views article has appeared regarding our published work on manipulating the superconducting gap at atomic scale.

January 2020
The paper by Freek Massee and collaborators on tuning the superconducting gap of Bi2Sr2CaCu2O8+x by manipulating atoms has appeared into Science .

January 2020
Umamahesh Thupakula has started a post-doc to work with our STM.

September 2019
Alexandra Palacio Morales has joined the group as an Assistant Professor.

July 2019
A news and views article has appeared regarding our published work on high kinetic inductance W nanowires.

June 2019
The french version of the smartphone application Phyphox has been released. The translation was driven by Frédéric Bouquet (Université Paris Sud), Ulysse Delabre (Université de Toulouse) and Julien Basset, assistant professor in the group.

November 2017
Cyril Vaneph has successfully defended his thesis.

October 2017
Freek Massee has started as a 'Chargé de Recherche' with the CNRS. He remains in the group.

June 2017
Aymeric Courilleau and Baptiste Jost have joined us as interns.

April 2017
Félicien Appas has joined us as an intern.

March 2017
Charis Quay has been awarded a Bronze Medal by the CNRS.

January 2017
Pierre Février has successfully defended his thesis.

September 2016
Marko Kuzmanović and Gianluca Aiello have joined the group as PhD students.

June 2016
Nikhita Baladari has joined us as an intern.

May 2016
Faten Ben Chaabane, Alexander Noddings and Mohamed Ouerfelli have joined us as interns.

March 2016
Marko Kuzmanović has returned to the group as an intern.

February 2016
Bi Yi Wu is visiting 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 and Gianluca Aiello has joined as an intern.

July 2015
Julien Basset and his colleagues at ETH Zurich published in PRL.

June 2015
Pierre Chevalier and Clément Leroy have joined as interns.

May 2015
Charles Rigoudy has joined as an intern.

April 2015 Our work on spin resonance of quasiparticles in superconducting aluminium has been published in Nature Communications.

February 2015
Freek Massee has joined the group as a postodoc.

January 2015
Cyril Vaneph has joined as a PhD student. Alexis Morvan and Mathieu Féchant have joined as interns.

October 2014
Jérôme Estève has joined the group. Marko Kuzmanović has joined as an intern.

September 2014
Julien Basset has joined the group. Maximilian Weideneder will be spending the academic year with us as part of his diplomarbeit. Tom Dvir is visiting us and the Mesoscopic Physics group for a few weeks.

August 2014
Our work on the spin (imbalance) lifetime in a superconductor in the frequency domain is published. Experiment, Theory.

May 2014
Yann Chiffaudel has joined as an intern. Christoph Strunk is visiting the group.

April 2014
Jordan Bouaziz has joined as an intern.

January 2014
Tito Williams has joined as a visitor.

November 2013
Our work on a third-order correlator of the electromagnetic field is published in New Journal of Physics, arXiv.

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' arXiv, Nature Physics.

January 2013
Baydir Bouali and Pierre Février have joined as interns, Edouard Pinsolle as a postdoc.

August 2012
We have shown that it is possible to have spin imbalance but not charge imbalance (and vice versa) arXiv, Nature Physics, News and Views.

July 2012
Marco Aprili will be on sabbatical this coming academic year at Cornell University.