400 research outputs found
Computing the steady states for an asymptotic model of quantum transport in resonant heterostructures
In this article we propose a rapid method to compute the steady states, including bifurcation diagrams, of resonant tunneling heterostructures in the far from equilibrium regime. Those calculations are made on a simplified model which takes into account the characteristic quantities which arise from an accurate asymptotic analysis of the nonlinear Schrödinger-Poisson system. After a summary of the former theoretical results, the asymptotical model is explicitly adapted to physically realistic situations and numerical results are shown in various cases. UNE VERSION MODIFIEE DE CE TEXTE EST PARUE DANS J. COMPUT. PHYS
Spin characterization and control over the regime of radiation-induced zero-resistance states
Over the regime of the radiation-induced zero-resistance states and
associated oscillatory magnetoresistance, we propose a low magnetic field
analog of quantum-Hall-limit techniques for the electrical detection of
electron spin- and nuclear magnetic- resonance, dynamical nuclear polarization
via electron spin resonance, and electrical characterization of the nuclear
spin polarization via the Overhauser shift. In addition, beats observed in the
radiation-induced oscillatory-magnetoresistance are developed into a method to
measure and control the zero-field spin splitting due to the Bychkov-Rashba and
bulk inversion asymmetry terms in the high mobility GaAs/AlGaAs system.Comment: IEEE Transactions in Nanotechnology (to be published); 10 pages, 10
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An explicit model for the adiabatic evolution of quantum observables driven by 1D shape resonances
This paper is concerned with a linearized version of the transport problem
where the Schr\"{o}dinger-Poisson operator is replaced by a non-autonomous
Hamiltonian, slowly varying in time. We consider an explicitly solvable model
where a semiclassical island is described by a flat potential barrier, while a
time dependent 'delta' interaction is used as a model for a single quantum
well. Introducing, in addition to the complex deformation, a further
modification formed by artificial interface conditions, we give a reduced
equation for the adiabatic evolution of the sheet density of charges
accumulating around the interaction point.Comment: latex; 26 page
Far from equilibrium steady states of 1D-Schrödinger-Poisson systems with quantum wells I
We describe the asymptotic of the steady states of the out-of equilibrium Schrödinger-Poisson system, in the regime of quantum wells in a semiclassical island. After establishing uniform estimates on the nonlinearity, we show that the nonlinear steady states lie asymptotically in a finite-dimensional subspace of functions and that the involved spectral quantities are reduced to a finite number of so-called asymptotic resonant energies. The asymptotic finite dimensional nonlinear system is written in a general setting with only a partial information on its coefficients. After this first part, a complete derivation of the asymptotic nonlinear system will be done for some specific cases in a forthcoming article. UNE VERSION MODIFIEE DE CE TEXTE EST PARUE DANS LES ANNALES DE L'INSTITUT H. POINCARE, ANALYSE NON LINEAIRE
Adiabatic evolution of 1D shape resonances: an artificial interface conditions approach
Artificial interface conditions parametrized by a complex number
are introduced for 1D-Schr\"odinger operators. When this complex parameter
equals the parameter of the complex deformation which unveils
the shape resonances, the Hamiltonian becomes dissipative. This makes possible
an adiabatic theory for the time evolution of resonant states for arbitrarily
large time scales. The effect of the artificial interface conditions on the
important stationary quantities involved in quantum transport models is also
checked to be as small as wanted, in the polynomial scale as
, according to .Comment: 60 pages, 13 figure
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