Laboratoire Pierre Aigrain
Présentation
Le Laboratoire Pierre Aigrain (LPA) est concerné par divers aspects fondamentaux de la nano-physique : boîtes quantiques et microcavités de semiconducteurs, structures conductrices mésoscopiques, films minces supraconducteurs, molécules uniques carbonées (nanotubes) ou biologiques (ADN). Il étudie d’un point de vue expérimental et théorique ces nano-objets dont les possibilités d’application couvrent des domaines aussi diversifiés que l’optoélectronique, l’information quantique, l’électronique moléculaire, la reconnaissance électronique des molécules biologiques. Il travaille en particulier grâce à un réseau de collaborations nationales et internationales (CNRS/CRHEA Valbonne, CEA/CNRS Grenoble, CEA/Saclay, Universités d’Orsay, de Tokyo, de Californie à Santa Barbara, Institut Pasteur, Département de biologie de l’ENS, Max-Planck Institüt, LCR-Thalès, Alcatel, Motorola), sans oublier son partenaire privilégié, le Laboratoire de Photonique et Nanostructures de Marcoussis.
Les techniques expérimentales sont celles de la spectroscopie optique classique ou laser, linéaire ou non linéaire, des mesures de transport électrique en régime continu ou radiofréquence, des mesures de force à l’échelle du piconewton. S’y ajoute une importante activité théorique.
Le Laboratoire compte une soixantaine de personnes: chercheurs, enseignant-chercheurs, ingénieurs et techniciens, doctorants, post-doctorants. Il est divisé en six équipes expérimentales auxquelles s’ajoutent l’équipe théorique, une équipe d'instrumentation et un service administratif. Il participe activement aux activités d'enseignement de l'ENS et des universités Paris Diderot et Paris 6.
Jean-Marc Berroir
Thèmes de recherche
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Biophysique
- Physique du vivant : Moteurs moléculaires et interactions ADN-protéines à l'échelle de la molécule unique: mesures de force par piège optique et pince magnétique
- Physique de l'ADN : Approches physiques de la biologie moléculaire: manipulation de molécules uniques, mesures de force par pièges optiques et mesures électroniques
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Propriété électronique des nano-objets
- Optique cohérente et non-linéaire : Nouveaux Matériaux et microcavités, Propriétés opto-électroniques des hétérostructures
- Infra-rouge lointain : Magnétospectroscopie des nanostructures dans l'infrarouge lointain
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Théorie
- Propriétés électroniques des nano-objets
- Systèmes fortement corrélés et mésoscopiques : effet Hall quantique fractionnaire, liquides de Luttinger, magnétisme en basses dimensions
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Physique Mésoscopique - Transport
- Physique Mésoscopique : transport mésoscopique hyperfréquence, transport électronique à l'échelle atomique
- Transport : Dynamique du paramètre d'ordre supraconducteur et des vortex
[hal-00533111] Superconducting nanowire single electron detector
Date: 5 11 月 2010 - 11:22
Desc: WE REPORT THE DETECTION OF SINGLE ELECTRONS USING A 6 NM-THICK, 100 NM-WIDE, NB0.7TI0.3N SUPERCONDUCTING STRIP DEPOSITED ON A SIOX/SI SUBSTRATE. WHEN BIASED SLIGHTLY BELOW THE CRITICAL CURRENT, A MEANDER-SHAPED DEVICE, NOT ONLY DETECTS SINGLE PHOTONS, BUT ALSO COUNTS THE SINGLE KEV ELECTRONS ISSUED FROM A SCANNING ELECTRON MICROSCOPE (SEM) WITH AN EFFICIENCY APPROACHING UNITY. THE RESPONSE TIME IS SHORT ENOUGH TO DISCRIMINATE THE INCIDENT ELECTRONS FROM THOSE BACKSCATTERED FROM THE UNDERLYING MATERIAL. IT IS THEREFORE POSSIBLE TO MAP THE ELECTRON DETECTIVITY AS WELL AS THE PHOTON DETECTIVITY ON THE SAME DEVICE. A CLEAR CORRELATION BETWEEN THE TWO MEASUREMENTS IS OBSERVED, WITH A SUPERIOR SPATIAL RESOLUTION THOUGH (AROUND 100 NM) FOR THE SEM MAPPING. IT ILLUSTRATES THE POTENTIAL USE OF THIS SINGLE ELECTRON MAPPING BY THE SEM METHOD TO CHARACTERIZE THE DETECTION HOMOGENEITY OF SSPDS
[hal-00436122] Spin-dependent boundary conditions for isotropic superconducting Green's functions
Date: 26 11 月 2009 - 10:40
Desc: The quasiclassical theory of superconductivity provides the most successful description of diffusive heterostructures comprising superconducting elements, namely, the Usadel equations for isotropic Green's functions. Since the quasiclassical and isotropic approximations break down close to interfaces, the Usadel equations have to be supplemented with boundary conditions for isotropic Green's functions (BCIGF), which are not derivable within the quasiclassical description. For a long time, the BCIGF were available only for spin-degenerate tunnel contacts, which posed a serious limitation on the applicability of the Usadel description to modern structures containing ferromagnetic elements. In this article, we close this gap and derive spin-dependent BCIGF for a contact encompassing superconducting and ferromagnetic correlations. This finally justifies several simplified versions of the spin-dependent BCIGF, which have been used in the literature so far. In the general case, our BCIGF are valid as soon as the quasiclassical isotropic approximation can be performed. However, their use require the knowledge of the full scattering matrix of the contact, an information usually not available for realistic interfaces. In the case of a weakly polarized tunnel interface, the BCIGF can be expressed in terms of a few parameters, i.e. the tunnel conductance of the interface and five conductance-like parameters accounting for the spin-dependence of the interface scattering amplitudes. In the case of a contact with a ferromagnetic insulator, it is possible to find explicit BCIGF also for stronger polarizations. The BCIGF derived in this article are sufficienly general to describe a variety of physical situations and may serve as a basis for modelling realistic nanostructures.
[hal-00533120] A high efficiency superconducting nanowire single electron detector
Date: 21 5 月 2021 - 14:28
Desc: [...]
[hal-01540470] Josephson junction dynamics in the presence of $2\pi$- and $4\pi$-periodic supercurrents
Date: 16 6 月 2017 - 14:07
Desc: We investigate theoretically the dynamics of a Josephson junction in the framework of the RSJ model. We consider a junction that hosts two supercurrrent contributions: a $2\pi$- and a $4\pi$-periodic in phase, with intensities $I_{2\pi}$ and $I_{4\pi}$ respectively. We study the size of the Shapiro steps as a function of the ratio of the intensity of the mentioned contributions, i.e. $I_{4\pi}/I_{2\pi}$. We provide detailed explanations where to expect clear signatures of the presence of the $4\pi$-periodic contribution as a function of the external parameters: the intensity AC-bias $I_\text{ac}$ and frequency $\omega_\text{ac}$. On the one hand, in the low AC-intensity regime (where $I_\text{ac}$ is much smaller than the critical current, $I_\text{c}$), we find that the non-linear dynamics of the junction allows the observation of only even Shapiro steps even in the unfavorable situation where $I_{4\pi}/I_{2\pi}\ll 1$. On the other hand, in the opposite limit ($I_\text{ac}\gg I_\text{c}$), even and odd Shapiro steps are present. Nevertheless, even in this regime, we find signatures of the $4\pi$-supercurrent in the beating pattern of the even step sizes as a function of $I_\text{ac}$.
[hal-02318661] A graphene Zener–Klein transistor cooled by a hyperbolic substrate
Date: 17 10 月 2019 - 13:09
Desc: [...]
Autres contacts
Ecole Normale Supérieure (Paris-Ulm)
Bâtiment de Physique
1er étage - pièces D17-D13
24, rue Lhomond
75205 PARIS CEDEX 13