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(419) Production(s) de l'année 2017
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Radiative heat transfer between metallic gratings using Fourier modal method with adaptive spatial resolution
Auteur(s): Messina R., Noto A., Guizal B., Antezza M.
(Article) Publié:
Physical Review B, vol. 95 p.125404 (2017)
Texte intégral en Openaccess :
Ref HAL: hal-01482013_v1
DOI: 10.1103/PhysRevB.95.125404
WoS: 000396010400005
Exporter : BibTex | endNote
25 Citations
Résumé: We calculate the radiative heat transfer between two identical metallic one-dimensional lamellar gratings. To this aim we present and exploit a modification to the widely used Fourier modal method, known as adaptive spatial resolution, based on a stretch of the coordinate associated with the periodicity of the grating. We first show that this technique dramatically improves the rate of convergence when calculating the heat flux, allowing us to explore smaller separations. We then present a study of heat flux as a function of the grating height, highlighting a remarkable amplification of the exchanged energy, ascribed to the appearance of spoof-plasmon modes, whose behavior is also spectrally investigated. Differently from previous works, our method allows us to explore a range of grating heights extending over several orders of magnitude. By comparing our results to recent studies we find a consistent quantitative disagreement with some previously obtained results going up to 50%. In some cases, this disagreement is explained in terms of an incorrect connection between the reflection operators of the two gratings.
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Analytical results for a coagulation/decoagulation model on an inhomogeneous lattice
Auteur(s): Crampé N.
(Article) Publié:
Scipost Physics, vol. 2 p.006 (2017)
Texte intégral en Openaccess :
Ref HAL: hal-01480834_v1
Ref Arxiv: 1612.07036
DOI: 10.21468/SciPostPhys.2.1.006
WoS: 000410371200006
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
1 Citation
Résumé: We show that an inhomogeneous coagulation/decoagulation model can be mapped to a quadratic fermionic model via a Jordan-Wigner transformation. The spectrum for this inhomogeneous model is computed exactly and the spectral gap is described for some examples. We construct our inhomogeneous model from two different homogeneous models joined by one special bond (impurity). The homogeneous models we started with are the coagulation/decoagulation models studied previously using the Jordan-Wigner transformation.
Commentaires: . Réf Journal: SciPost Phys. 2, 006 (2017)
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Overtones of interlayer shear modes in the phonon-assisted emission spectrum of hexagonal boron nitride
Auteur(s): Vuong P., Cassabois G., Valvin P., Jacques V., Cusco R., Artus L., Gil B.
(Article) Publié:
Physical Review B, vol. 95 p.045207 (2017)
Texte intégral en Openaccess :
Ref HAL: hal-01475800_v1
DOI: 10.1103/PhysRevB.95.045207
WoS: WOS:000392074700012
Exporter : BibTex | endNote
16 Citations
Résumé: We address the intrinsic optical properties of hexagonal boron nitride in the deep ultraviolet. Weshow that the fine structure of the phonon replicas arises from overtones involving up to six low-energy interlayer shear modes. These lattice vibrations are specific to layered compounds since theycorrespond to the shear rigid motion between adjacent layers, with a characteristic energy of about6-7 meV. We obtain a quantitative interpretation of the multiplet observed in each phonon replicaunder the assumption of a cumulative Gaussian broadening as a function of the overtone index,and with a phenomenological line-broadening taken identical for all phonon types. We show fromour quantitative interpretation of the full emission spectrum above 5.7 eV that the energy of theinvolved phonon mode is 6.8±0.5 meV, in excellent agreement with temperature-dependent Ramanmeasurements of the low-energy interlayer shear mode in hexagonal boron nitride. We highlightthe unusual properties of this material where the optical response is tailored by the phonon groupvelocities in the middle of the Brillouin zone.
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Stacking fault and defects in single domain multilayered hexagonal boron nitride
Auteur(s): Henck Hugo, Pierucci Debora, Ben Aziza Zeineb, Silly Mathieu G., Gil B., Sirotti Fausto, Cassabois G., Ouerghi Abdelkarim
(Article) Publié:
Applied Physics Letters, vol. 110 p.023101 (2017)
Ref HAL: hal-01475792_v1
DOI: 10.1063/1.4972848
WoS: WOS:000392835300048
Exporter : BibTex | endNote
11 Citations
Résumé: Two dimensional materials like graphene, transition metal dichalcogenides, and hexagonal boron nitride (h-BN) have attracted a keen interest over the past few years due to their possible integration in the next generation of nano-components. Here, we used high resolution X-ray photoemission spectroscopy and near-edge X-ray absorption fine structure (NEXAFS) to perform a complete study of stacking configuration and identify sp3 crystal deformations of a single domain h-BN crystal. The AA′ stacking was found to best reproduce features in the experimental B and N K-edges. The NEXAFS also shows that the splitting of the 1s to π* peak in the B K-edge, recently predicted by density functional theory, may be accounted for by the presence of AB′ stacking faults. The presence of this stacking fault has, as a result, the introduction of point defects in the crystal such as boron atoms in a pyramidal or sp3 configuration. Interstitial nitrogen defects are also present in the crystal forming a N-N pair as expected for a p-type h-BN crystal.
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Bursting mechanism of dilute emulsion-based liquid sheets: anti-drift application for agricultural sprays
Auteur(s): Ligoure C.
Conférence invité: CROPS AND CHEMICALS EUROPE (BERLIN, DE, 2017-02-08)
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Stem cells as anticancer drug delivery to reduce the chemotherapy side effect
Auteur(s): Salehi Hamideh, Al-Arag Siham, Middendrop Elodie, Gergely C., Cuisinier Frédéric
Conference: SPIE Photonics west 2017 (San Francisco, US, 2017)
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Many body heat radiation and heat transfer in the presence of a non-absorbing background medium
Auteur(s): Boris Muller, Roberta Incardone, Antezza M., Thorsten Emig, Matthias Kruger
(Article) Publié:
Physical Review B, vol. 95 p.085413 (2017)
Texte intégral en Openaccess :
Ref HAL: hal-01464078_v1
DOI: 10.1103/PhysRevB.95.085413
WoS: 000393590900004
Exporter : BibTex | endNote
22 Citations
Résumé: Heat radiation and near-field radiative heat transfer can be strongly manipulated by adjusting geometrical shapes, optical properties, or the relative positions of the objects involved. Typically, these objects are considered as embedded in vacuum. By applying the methods of fluctuational electrodynamics, we derive general closed-form expressions for heat radiation and heat transfer in a system of N arbitrary objects embedded in a passive nonabsorbing background medium. Taking into account the principle of reciprocity, we explicitly prove the symmetry and positivity of transfer in any such system. Regarding applications, we find that the heat radiation of a sphere as well as the heat transfer between two parallel plates is strongly enhanced by the presence of a background medium. Regarding near- and far-field transfer through a gas like air, we show that a microscopic model (based on gas particles) and a macroscopic model (using a dielectric contrast) yield identical results. We also compare the radiative transfer through a medium like air and the energy transfer found from kinetic gas theory.
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