153 research outputs found
Eigenfunctions decay for magnetic pseudodifferential operators
We prove rapid decay (even exponential decay under some stronger assumptions)
of the eigenfunctions associated to discrete eigenvalues, for a class of
self-adjoint operators in defined by ``magnetic''
pseudodifferential operators (studied in \cite{IMP1}). This class contains the
relativistic Schr\"{o}dinger operator with magnetic field
Magnetic Fourier Integral Operators
In some previous papers we have defined and studied a 'magnetic'
pseudodifferential calculus as a gauge covariant generalization of the Weyl
calculus when a magnetic field is present. In this paper we extend the standard
Fourier Integral Operators Theory to the case with a magnetic field, proving
composition theorems, continuity theorems in 'magnetic' Sobolev spaces and
Egorov type theorems. The main application is the representation of the
evolution group generated by a 1-st order 'magnetic' pseudodifferential
operator (in particular the relativistic Schr\"{o}dinger operator with magnetic
field) as such a 'magnetic' Fourier Integral Operator. As a consequence of this
representation we obtain some estimations for the distribution kernel of this
evolution group and a result on the propagation of singularities
Spin tunneling through an indirect barrier
Spin-dependent tunneling through an indirect bandgap barrier like the
GaAs/AlAs/GaAs heterostructure along [001] direction is studied by the
tight-binding method. The tunneling is characterized by the proportionality of
the Dresselhaus Hamiltonians at and points in the barrier and by
Fano resonances. The present results suggest that large spin polarization can
be obtained for energy windows that exceed significantly the spin splitting. We
also formulate two conditions that are necessary for the existence of energy
windows with large polarization.Comment: 19 pages, 7 figure
Study of physical properties of some transparent oxides semiconductors obtained by thermal oxidation of metallic thin films
Date du colloque : 08/2013International audienc
Global exponential stability of classical solutions to the hydrodynamic model for semiconductors
In this paper, the global well-posedness and stability of classical solutions
to the multidimensional hydrodynamic model for semiconductors on the framework
of Besov space are considered. We weaken the regularity requirement of the
initial data, and improve some known results in Sobolev space. The local
existence of classical solutions to the Cauchy problem is obtained by the
regularized means and compactness argument. Using the high- and low- frequency
decomposition method, we prove the global exponential stability of classical
solutions (close to equilibrium). Furthermore, it is also shown that the
vorticity decays to zero exponentially in the 2D and 3D space. The main
analytic tools are the Littlewood-Paley decomposition and Bony's para-product
formula.Comment: 18 page
On the properties of ITO, ZnO, ZnO:Al and NiO thin films obtained by thermal oxidation
Date du colloque : 10/2014International audienc
Influence of PEDOTÂ :PSS Layer on the Performances of Photovoltaic Cells Based on MEH-PPV:PCBM Blend
Date du colloque : 07/2011International audienc
Optical, structural and morphological investigations for different metallic oxides
Date du colloque : 07/2013International audienc
Studies and optimizations of encapsulation antireflection glasses for silicon solar cells panels
Date du colloque : 10/2014International audienc
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