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Systèmes Complexes et Phénomènes Nonlinéaires
(31) Production(s) de l'année 2016
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Influence of magnetic quantum confined Stark effect on the spin lifetime of indirect excitons 
Auteur(s): Andreakou P., Mikhailov A. v., Cronenberger S., Scalbert D., Nalitov A., Kavokin A., Nawrocki M., Butov L. v., Campman K. l., Gossard A. c., Vladimirova M.
(Article) Publié:
Physical Review B, vol. 93 p.115410 (2016)
Texte intégral en Openaccess : 
DOI: 10.1103/PhysRevB.93.115410
WoS: WOS:000371734300008
4 Citations
Résumé: We report on the unusual and counterintuitive behavior of spin lifetime of excitons in coupled semiconductor quantum wells (CQWs) in the presence of in-plane magnetic field. Instead of conventional acceleration of spin relaxation due to the Larmor precession of electron and hole spins, we observe a strong increase of the spin relaxation time at low magnetic fields followed by saturation and decrease at higher fields. We argue that this nonmonotonic spin relaxation dynamics is a fingerprint of the magnetic quantum confined Stark effect. In the presence of electric field along the CQW growth axis, an applied magnetic field efficiently suppresses the exciton spin coherence, due to inhomogeneous broadening of the g-factor distribution.
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Soft spherical nanostructures with a dodecagonal quasicrystal-like order.
Auteur(s): Rochal S.B., Konevtsova O., Shevchenko I. A., Lorman V.
(Article) Publié:
Soft Matter, vol. 12 p.1238-47 (2016)
Ref HAL: hal-01259346_v1
PMID 26592422
DOI: 10.1039/c5sm02265g
WoS: 000369747900028
Exporter : BibTex | endNote
Résumé: We develop a theory which predicts curvature-related structural peculiarities of soft spherical nanostructures with a dodecagonal local arrangement of subunits. Spherical templates coated with a thin film of a soft quasicrystal (QC)-forming material constitute the most promising direction to realize these nanostructures. Disordered and perfect spherical nanostructures are simulated using two approaches. The first of them models a random QC-like spherical nanostructure with extended curvature-induced topological defects similar to scars in colloidal spherical crystals. The second approach is inspired by the physics of viral capsids. It deals with the most regular spherical nanostructures with a local QC-like order derived from three well-known planar dodecagonal tilings. We explain how the additional QC-like degrees of freedom assist the nanostructure stabilization and determine the point defect number and location without extended scar formation. Unusual for nanoassemblies snub cube geometry is shown to be the most energetically favorable global organization of these spherical QC nanostructures.
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Torque-Induced Rotational Dynamics in Polymers: Torsional Blobs and Thinning
Auteur(s): Laleman Michiel, Baiesi Marco, Belotserkovskii Boris P., Sakaue Takahiro, Walter J.-C., Carlon Enrico
(Article) Publié:
Macromolecules, vol. 2016 p.405-414 (2016)
Texte intégral en Openaccess : 
Ref HAL: hal-01254327_v1
Ref Arxiv: 1602.00551
DOI: 10.1021/acs.macromol.5b01481
WoS: 000368322000045
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
4 Citations
Résumé: By using the blob theory and computer simulations, we investigate the properties of a linear polymer performing a stationary rotational motion around a long impenetrable rod. In particular, in the simulations the rotation is induced by a torque applied to the end of the polymer that is tethered to the rod. Three different regimes are found, in close analogy with the case of polymers pulled by a constant force at one end. For low torques the polymer rotates maintaining its equilibrium conformation. At intermediate torques the polymer assumes a trumpet shape, being composed by blobs of increasing size. At even larger torques the polymer is partially wrapped around the rod. We derive several scaling relations between various quantities as angular velocity, elongation and torque. The analytical predictions match the simulation data well. Interestingly, we find a "thinning" regime where the torque has a very weak (logarithmic) dependence on the angular velocity. We discuss the origin of this behavior, which has no counterpart in polymers pulled by an applied force.
Commentaires: 30 pages, 8 figures, 1 TOC figure; video abstract at https://youtu.be/LwicoSkh3mI. Réf Journal: Macromolecules, 2016, 49 (1), 405-414
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