CNRS Physics Laboratory of Condensed Matter and Nanostructure

Lyon, France

CNRS Physics Laboratory of Condensed Matter and Nanostructure

Lyon, France

Time filter

Source Type

Chaudhuri P.,CNRS Physics Laboratory of Condensed Matter and Nanostructure | Mansard V.,CNRS Laboratory of Future | Colin A.,CNRS Laboratory of Future | Bocquet L.,CNRS Physics Laboratory of Condensed Matter and Nanostructure
Physical Review Letters | Year: 2012

Using numerical simulations, we study the gravity driven flow of jammed soft disks in confined channels. We demonstrate that confinement results in increasing the yield threshold for the Poiseuille flow, in contrast to the planar Couette flow. By solving a nonlocal flow model for such systems, we show that this effect is due to the correlated dynamics responsible for flow, coupled with the stress heterogeneity imposed for the Poiseuille flow. We also observe that with increasing confinement, the cooperative nature of the flow results in increasing intermittent behavior. Our studies indicate that such features are generic properties of a wide variety of jammed materials. © 2012 American Physical Society.


Biance A.-L.,University Claude Bernard Lyon 1 | Biance A.-L.,CNRS Physics Laboratory of Condensed Matter and Nanostructure | Delbos A.,University Paris Est Creteil | Pitois O.,University Paris Est Creteil
Physical Review Letters | Year: 2011

The stability of foam is investigated experimentally through coalescence events. Instability (coalescence) occurs when the system is submitted to external perturbations (T1) and when the liquid amount in the film network is below a critical value. Microscopically, transient thick films are observed during film rearrangements. Film rupture, with coalescence and eventual collapse of the foam, occurs when the available local liquid amount is too small for transient films to be formed. Similar experiments and results are shown in the two-bubble case. © 2011 American Physical Society.


Chaudhuri P.,CNRS Physics Laboratory of Condensed Matter and Nanostructure | Berthier L.,Montpellier University | Sastry S.,Jawaharlal Nehru Centre for Advanced Scientific Research
Physical Review Letters | Year: 2010

We numerically produce fully amorphous assemblies of frictionless spheres in three dimensions and study the jamming transition these packings undergo at large volume fractions. We specify four protocols yielding a critical value for the jamming volume fraction which is sharply defined in the limit of large system size, but is different for each protocol. Thus, we directly establish the existence of a continuous range of volume fractions where nonequilibrium jamming transitions occur. However, these jamming transitions share the same critical behavior. Our results suggest that, even in the absence of partial crystalline ordering, a unique location of a random close packing does not exist. © 2010 The American Physical Society.


Bruneval F.,CEA Saclay Nuclear Research Center | Marques M.A.L.,University of Lyon | Marques M.A.L.,CNRS Physics Laboratory of Condensed Matter and Nanostructure
Journal of Chemical Theory and Computation | Year: 2013

The GW approximation is nowadays being used to obtain accurate quasiparticle energies of atoms and molecules. In practice, the GW approximation is generally evaluated perturbatively, based on a prior self-consistent calculation within a simpler approximation. The final result thus depends on the choice of the self-consistent mean-field chosen as a starting point. Using a recently developed GW code based on Gaussian basis functions, we benchmark a wide range of starting points for perturbative GW, including Hartree-Fock, LDA, PBE, PBE0, B3LYP, HSE06, BH&HLYP, CAM-B3LYP, and tuned CAM-B3LYP. In the evaluation of the ionization energy, the hybrid functionals are clearly superior results starting points when compared to Hartree-Fock, to LDA, or to the semilocal approximations. Furthermore, among the hybrid functionals, the ones with the highest proportion of exact-exchange usually perform best. Finally, the reliability of the frozen-core approximation, that allows for a considerable speed-up of the calculations, is demonstrated. © 2012 American Chemical Society.


Jop P.,University of Bordeaux 1 | Mansard V.,University of Bordeaux 1 | Chaudhuri P.,CNRS Physics Laboratory of Condensed Matter and Nanostructure | Bocquet L.,CNRS Physics Laboratory of Condensed Matter and Nanostructure | Colin A.,University of Bordeaux 1
Physical Review Letters | Year: 2012

Using confocal microscopy, we study the flow of a model soft glassy material: a concentrated emulsion. We demonstrate the micro-macro link between in situ measured movements of droplets during the flow and the macroscopic rheological response of a concentrated emulsion, in the form of scaling relationships connecting the rheological "fluidity" with local standard deviation of the strain-rate tensor. Furthermore, we measure correlations between these local fluctuations, thereby extracting a correlation length which increases while approaching the yielding transition, in accordance with recent theoretical predictions. © 2012 American Physical Society.


Tournus F.,CNRS Physics Laboratory of Condensed Matter and Nanostructure
Journal of Nanoparticle Research | Year: 2011

We consider diluted assemblies of particles randomly distributed on a surface (2D samples), in a volume (3D samples) or in 2D layers separated with a spacer of thickness t (multilayer samples). Among various considerations on the inter-particle separations, a special interest is given to the nearest-neighbor distance distribution. We also discuss the influence of the particle size, by looking at the edge-to-edge distance, and analyze the particle distribution beyond the nearest-neighbor. Moreover, we investigate the particular case of multilayer samples, which to our knowledge has never been discussed. Finally, we experimentally illustrate the applicability of the random deposition model. © 2011 Springer Science+Business Media B.V.


Lee C.,CNRS Physics Laboratory of Condensed Matter and Nanostructure | Joly L.,CNRS Physics Laboratory of Condensed Matter and Nanostructure | Siria A.,CNRS Physics Laboratory of Condensed Matter and Nanostructure | Biance A.-L.,CNRS Physics Laboratory of Condensed Matter and Nanostructure | And 2 more authors.
Nano Letters | Year: 2012

Ion transport through nanopores drilled in thin membranes is central to numerous applications, including biosensing and ion selective membranes. This paper reports experiments, numerical calculations, and theoretical predictions demonstrating an unexpectedly large ionic conduction in solid-state nanopores, taking its origin in anomalous entrance effects. In contrast to naive expectations based on analogies with electric circuits, the surface conductance inside the nanopore is shown to perturb the three-dimensional electric current streamlines far outside the nanopore in order to meet charge conservation at the pore entrance. This unexpected contribution to the ionic conductance can be interpreted in terms of an apparent electric size of the solid-state nanopore, which is much larger than its geometric counterpart whenever the number of charges carried by the nanopore surface exceeds its bulk counterpart. This apparent electric size, which can reach hundreds of nanometers, can have a major impact on the electrical detection of translocation events through nanopores, as well as for ionic transport in biological nanopores. © 2012 American Chemical Society.


Delanoe-Ayari H.,University of Lyon | Rieu J.P.,University of Lyon | Rieu J.P.,CNRS Physics Laboratory of Condensed Matter and Nanostructure | Sano M.,University of Tokyo
Physical Review Letters | Year: 2010

We present a 4D (x; y; z; t) force map of Dictyostelium cells crawling on a soft gel substrate. Vertical forces are of the same order as the tangential ones. The cells pull the substratum upward along the cell, medium, or substratum contact line and push it downward under the cell except for the pseudopods. We demonstrate quantitatively that the variations in the asymmetry in cortical forces correlates with the variations of the direction and speed of cell displacement. © 2010 The American Physical Society.


Joly L.,CNRS Physics Laboratory of Condensed Matter and Nanostructure
Journal of Chemical Physics | Year: 2011

This article discusses the way the standard description of capillary filling dynamics has to be modified to account for liquid/solid slip in nanometric pores. It focuses, in particular, on the case of a large slip length compared to the pore size. It is shown that the liquid viscosity does not play a role, and that the flow is only controlled by the friction coefficient of the liquid at the wall. Moreover, in the Washburn regime, the filling velocity does not depend on the tube radius. Finally, molecular dynamics simulations suggest that this standard description fails to describe the early stage of capillary filling of carbon nanotubes by water, since viscous dissipation at the tube entrance must be taken into account. © 2011 American Institute of Physics.


Tournus F.,CNRS Physics Laboratory of Condensed Matter and Nanostructure
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2011

Efforts are currently under way to produce nanoparticle samples with a size dispersion as low as possible, using deposition of preformed clusters on a substrate. However, even for diluted cluster films, contact or coalescence between neighboring clusters cannot be totally avoided due to the random nature of the deposition process. Consequently, the incident particle-size distribution will necessarily be degraded, with the statistical formation of multimers (dimers, trimers, or more generally nmers). In this article, we consider diluted assemblies of nanoparticles (with a narrow size distribution) randomly deposited on a surface and develop theoretical tools to assess the various multimer proportions. We establish simple and reliable analytical approximations of the probability for a cluster to form an nmer and the subsequent multimer proportion. These results can be applied in the analysis of experimental samples: They constitute a convenient tool for experimentalists in the design of their nanoparticle sample and the interpretation of experimental measurements. © 2011 American Physical Society.

Loading CNRS Physics Laboratory of Condensed Matter and Nanostructure collaborators
Loading CNRS Physics Laboratory of Condensed Matter and Nanostructure collaborators