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11.
A. Ben Ali M. Héritier S. Charfi-Kaddour R. Bennaceur 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,14(1):53-61
A model of quasi-two-dimensional d-wave superconductor, with strong nesting properties of the Fermi surface is considered. The orbital effect of a moderate
magnetic field applied perpendicularly to the conducting planes is studied in the mean field approximation. It is shown that
the field can induce a time reversal symmetry breaking SDW order coexisting with the superconducting order and can open a
gap over the whole Fermi surface. The anomalies recently observed in the heat conductivity in might be ascribed to this effect.
Received 7 May 1999 and Received in final form 13 August 1999 相似文献
12.
H.?Eleuch N.?Ben?NessibEmail author R.?Bennaceur 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2004,29(3):391-395
We present, in this work a simple analytical expression of line emission in weakly non ideal plasma using a simplified quantum model. This formalism allows to explain the variations of the line widths with the density in a weakly non ideal plasma. We apply this model to plasma neutral helium lines HeI 6678 Å and HeI 5876 Å and explain the non linearity of the line width.Received: 17 January 2004, Published online: 4 May 2004PACS:
32.70.Jz Line shapes, widths, and shifts - 31.15.Lc Quasiparticle methods - 42.50.-p Quantum optics 相似文献
13.
This work presents the first continuum shell-model study of weakly bound neutron-rich nuclei involving multiconfiguration mixing. For the single-particle basis, the complex-energy Berggren ensemble representing the bound single-particle states, narrow resonances, and the nonresonant continuum background is taken. Our shell-model Hamiltonian consists of a one-body finite potential and a zero-range residual two-body interaction. It is demonstrated that the residual interaction coupling to the particle continuum is important; in some cases, it can give rise to the binding of a nucleus. 相似文献
14.
Jichen Zhang Dr. Zhiyong Wang Salima Bennaceur Prof. Xianbo Jin 《Angewandte Chemie (International ed. in English)》2023,62(19):e202301479
The carbon to CaC2 route is promising to provide a sustainable elementary unit, C2H2, for the organic synthesis industry, but the traditional thermal reaction process suffers from low carbon efficiency, harmful gas contamination, high temperature operation, and risky CO management. We herein report a high carbon efficiency (ca. 100 %) conversion of biochar to C2H2 through an electrolytic synthesis of solid CaC2 in molten CaCl2/KCl/CaO at 973 K. The main reactions are carbon reduction to CaC2 at the solid carbon cathode and oxygen evolution at an inert anode. Meanwhile, the electrolysis removes S and P from the solid cathode, avoiding the formation of CaS and Ca3P2 in CaC2 and consequently eliminating H2S and PH3 contamination in the finally produced C2H2. 相似文献
15.
N. Jebbari F. Saadallah C. Guasch N. Kamoun Turki N. Yacoubi R. Bennaceur 《Applied Physics A: Materials Science & Processing》2014,116(4):2011-2017
Aluminum-doped indium sulfide thin films are deposited on glass by spray pyrolysis technique. The structure and the surface morphology of these films were characterized by X-ray diffraction and atomic force microscopy. The effects of aluminum ratio z and substrate temperature T s, on the film structure and grain size are discussed. The influence of aluminum ratio on surface morphology is revealed by scanning electron microscope. Besides, energy dispersive spectrometry technique is used to compare atomic aluminum concentration in the film with aluminum ratio z in spray solution. Optical properties are studied by a spectrophotometer in the wavelength range 350–850 nm, at room temperature. Optical transmission and grain size are found to be maximal for z = 1.8 %. Moreover, band-gap energy is found to increase with aluminum ratio. 相似文献
16.
This paper reports a study of the application of chemical vapor-etching (CVE) for the rear surface and in the emitter of polycrystalline silicon (pc-Si) solar cells. The CVE technique consists of exposing pc-Si wafers to a mixture of HF/HNO3. This technique is used to groove the rear surface of the pc-Si wafers for acid vapors rich in HNO3 (HNO3/HF > 1/4), in order to realize rear-buried metallic contacts (RBMC) and the formation of a porous silicon (PS) layer on the frontal surface of the cell for volume ratio of HNO3/HF = 1/7. A significant increase of the spectral response in the long wavelength range was observed when a RBMC is formed. This increase was attributed to the reduction of the effective thickness of the base of the cells and grain boundary Al gettering. The achievement of a PS layer on the emitter of the pc-Si cells passivates the surface and reduces the reflectivity. The dark I-V characteristics of pc-Si cells with emitter-based PS show an important reduction of the reverse current together with an improvement of the rectifying behaviour. The I-V characteristic under AM1.5 illumination shows an enhancement of both short circuit current density and fill factor. The internal quantum efficiency is improved, particularly in the short wavelengths region. 相似文献
17.
Y. Turki-Ben Ali R. Bennaceur 《Physica E: Low-dimensional Systems and Nanostructures》2005,28(4):347-354
The aim of this work is to analyze theoretically the correlation energies for neutral, positively, negatively charged exciton and bi-exciton. So, we propose a model consistent with experimental observations that is small InAs truncated pyramids with circular base lying on wetting layer, both buried into GaAs matrix.In a first step and in contrast to other works, we are able to evaluate coulombic interactions between electron and hole, two electrons and two holes by perturbative method at the second order. In a second step, the correlation energies of many-body complexes X, X-, X+ and XX are investigated as a function of quantum dots basis radius rc and the applied electric field.Our main goal is to provide realistic estimation for the correlation energies of excitons, charged excitons and bi-excitons while retaining at the same time a transparent formalism, which could easily be transposed to structures of actual interest.The present work provides evidence of the stability of excitons, charged excitons and bi-excitons in InAs/GaAs quantum dots. Calculated correlation energies of many-body complexes are consistent with those reported by recent photoluminescence measurements. 相似文献
18.
S. Haddad M. Héritier R. Bennaceur 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,11(3):429-437
By setting up the relevant recursion relations and by doing exact and approximate calculations, we show that there is no critical
dimension in a self-avoiding random walk on a simplex fractal.
Received: 6 April 1998 / Revised: 4 August 1998 / Accepted: 26 August 1998 相似文献
19.
T. Lesinski T. Duguet K. Bennaceur J. Meyer 《The European Physical Journal A - Hadrons and Nuclei》2009,40(2):121-126
We perform systematic calculations of pairing gaps in semi-magic nuclei across the nuclear chart using the Energy Density
Functional method and a non-empirical pairing functional derived, without further approximation, at lowest order in the two-nucleon vacuum interaction, including
the Coulomb force. The correlated single-particle motion is accounted for by the SLy4 semi-empirical functional. Rather unexpectedly,
both neutron and proton pairing gaps thus generated are systematically close to experimental data. Such a result further suggests
that missing effects, i.e. higher partial waves of the NN interaction, the NNN interaction and the coupling to collective fluctuations, provide an overall
contribution that is sub-leading as for generating pairing gaps in nuclei. We find that including the Coulomb interaction
is essential as it reduces proton pairing gaps by up to 40%. 相似文献
20.
S. Charfi-Kaddour R. Louati A. Ben Ali R. Bennaceur M. Héritier 《Hyperfine Interactions》2001,133(1-4):245-251
The -(BEDT-TTF)2X organic superconductors are described by a two parameter 2D Fermi surface model, in which bandwidth and departure from perfect nesting can be varied. We have studied the spin fluctuations effect on the normal state properties in a Fermi liquid approach using the RPA approximation. The calculated NMR relaxation rate exhibits a peak in 1/(T
1
T), which strongly decreases when the departure from perfect nesting of the Fermi surface and the bandwidth increase. These results are in good agreement with NMR experiments done in -(ET)2X at least qualitatively. In conclusion, we have shown that, in the normal state and with a Fermi liquid approach, the spin fluctuations, which are present in the system due to an imperfect nesting property of the Fermi surface, can induce anomalies of the magnetic properties. Besides, we can restore the usual behaviour like the Korringa law by increasing the bandwidth or by considering a more imperfect nesting. Our calculation reproduces qualitatively the applied pressure relaxation rate experiment done in -(ET)2X salt. 相似文献