12 Works

ZnTe/CdSe type-II core/shell spherical quantum dot under an external electric field

A. Chafai, I. Essaoudi, A. Ainane, F. Dujardin & R. Ahuja
We have investigated in the framework of the envelope function approximation and taking into account the dependence of the electron effective mass on radius the energy of an electron inside a ZnTe/CdSe core/shell spherical quantum dot. In order to make the problem more realistic, we describe the conduction band- edge alignment between core and shell materials by a finite height barrier. By applying the Ritz variational principle the effect of the electric field on the...

Lecture on the anomalous diffusion in Condensed Matter Physics

M. Benhamou
Diffusion is a natural or artificial process that governs many phenomena in nature. The most known diffusion is the Brownian or normal motion, where the mean-square-displacement of the tracer (diffusive particle among others) increases as the square-root of time. It is not the case, however, for complex systems, where the diffusion is rather slow, because at small-scales, these media present an heterogenous structure. This kind of slow motion is called subdiffusion, where the associated mean-square-displacement...

Extensive study of cage effect and subdiffusion in Pickering emulsions using molecular dynamics simulations

S. El Moudny, M. Benhamou, M. Badia & M. Ossmani
In this work, we aim at an extensive study of the diffusion phenomenon of oil-droplets dispersed in water onto which are strongly adsorbed charged point-like particles (Pickering emulsions). This diffusion that originates from multiple collisions with the molecules of water, is anomalous, due to the presence of relatively strong correlations between the moving oil-droplets. Using Molecular Dynamic simulation, with a pair-potential of Sogami-Ise type, we first observe that the random walkers execute a normal diffusion,...

Investigation of DNA denaturation from generalized Morse potential

R. El Kinani, H. Kaidi & M. Benhamou
In this paper, we present a non-linear model for the study of DNA denaturation transition. To this end, we assume that the double-strands DNA interact via a realistic generalized Morse potential that reproduces well the features of the real interaction. Using the Transfer Matrix Method, based on the resolution of a Schrödinger equation, we first determine exactly their solution, which are found to be bound states. Second, from an exact expression of the ground state,...

First principles calculations of electronic and optical properties for mixed perovskites: Ba(1-x)Ca(x)TiO3 and Ba(1-x)Sr(x)TiO3 (x=0.4, 0.6)

O. Tahiri, S. Kassou, R. El Mrabet & A. Belaaraj
The effect of Ca and Sr-doping on the structural electronic and optical properties of the cubic Ba(1- x)CaxTiO3 and Ba(1-x)SrxTiO3 (x=0.4, 0.6) mixed crystals was investigated using first-principles calculations based on density functional theory (DFT). The calculated band structures based on the optimized geometry of the cell for the solid solutions show an indirect band gap character at M-points, with low energy dispersion along height symmetry directions in the Brillouin zone. The band gaps increase...

Vortex phase transition and superconducting properties of organic quasi-two-dimensional k-(BEDT-TTF)2Cu[N(CN)2]Br

H. El Ouaddi, A. Tirbiyine, A. Taoufik, Y. Ait Ahmed, F. Chibane, H. Chaib, A. Nafidi & S. Snoussi
We report investigations of the low temperature dc susceptibility and the magnetization on the layered organic superconductor κ-(BEDT-TTF)2Cu[N(CN)2]Br near 80K and the effect of disorder on the superconducting transition temperature Tc. The shielding effect (S) and the critical current density Jc were studied (with H parallel to the c axis of the crystal). Jc can be estimated by analysis of magnetic hysteresis measurement using the Bean model. For each temperature value, we observed two regimes...

Carbon nanotubes functionalized with copper hexacyanoferrate nanoparticles for a selective extraction of cesium from liquid waste

H. Draouil, L. Alvarez, J. Causse, V. Flaud, M.A. Zaibi, J.L. Bantignies, M. Oueslati & J. Cambedouzou
Single-walled carbon nanotubes are functionalized with copper hexacyanoferrate nanoparticles for the liquid-solid extraction of cesium from liquid waste and contaminated water. The functionalization process is followed mainly by x-ray photoemission spectroscopy. Indeed, determining the chemical environment around carbon or nitrogen atoms allows to evidence the formation of covalent bounding. In addition, the signatures of iron and copper ions give information on the effective growth of hexacyanoferrate nanoparticles. Furthermore, the cesium sorption mechanism is investigated by...

Polymer nanocomposites from natural clay: Understanding clay-PEG interaction and their effect on spacing between clay-plates

S. Ghyati, M. Benhamou, M. El Jai & I. Akhrif
The interactions between clay-plates and hydrophilic polymer are investigated assuming that the polyethylene glycol chains are grafted onto face-to-face clay-plates. Besides the usual van der Waals attractive interaction, the clay-plates experience a repulsive effective interaction, due to the excluded volume force between monomers along the grafted PEG chains. The face-to-face clay- plates then play the role of polymer brushes. The free energy (per unit area) of a clay-plate pair is the sum of these interactions,...

Raman-active modes in defective peapod

F. Fergani, S.M. Ait Abdelkader, H. Chadli, A.H. Rahmani & A. Rahmani
The vibrational properties of defective single-walled carbon nanotube filled with C60 fullerene is the subject of the current study. For this aim we use the spectral moments method in the framework of the bond-polarization theory to calculate the nonresonant Raman spectra of hexa-vacancy defective C60 peapods. Essentially, the vibrational properties are closely coupled with the atomic structure of the system. The evolution of the Raman spectrum as a function of the spatial arrangement of defects...

ISPDS2 - Second International Symposium on Physics of Data Storage - Conference volume- Materials and Devices, Vol.2(3), 2017

J.L. Bantignies, L. Alvarez, P. Saint-Gregoire, M. Fouaidy, M. Benhamou, L. Khouchaf, A. Rahmani, Y. Gagou, A. Chahboun, A. Benyoussef, M. Boutahir, B.B. Balogun, J.C.R.E. Oliveira, C.T. Sousa, J.P. Araujo, A.H. Rahmani, H. Chadli, A. Neqali, H.El. Kaddoussi, A. Lahmar, M. Amjoud, A. Alimoussa, E. Choukri, H. Khimakhim, M. El Marssi … & I. Bouziani
The symposium ISPDS2 has taken place in Meknes (Morocco) in October, 2017. It has gathered specialists of various fields who presented their work in connection with the problematics of data storage. This conference volume contains 75 abstracts of communications presented at the meeting as invited conferences, talks, or posters. Various topics are covered.

Identification of mono- and few-layer graphene: Raman study

M. Boutahir, Ah Rahmani, H. Chadli & A. Rahmani
In this theoretical work, the Raman spectra were analyzed by considering the origin of the G peak, its shape, position and relative intensity as a function of the number of graphene layers. By using the spectral moment’s method, the Raman spectra of mono, bi and few-layers of graphene are calculated and a good agreement was found with group theory concerning the number of the Raman-active modes and the Raman measurements. Our results provide a Raman...

Raman active modes of single-wall boron nitride nanotubes inside carbon nanotubes

A.M. Nassir, AH. Rahmani, M. Boutahir, B. Fakrach, H. Chadli & A. Rahmani
The structure of boron–nitride nanotubes (BNNTs) is very similar to that of CNTs, and they exhibit many similar physical and chemical properties. In particular, a single walled boron nitride nanotube (BNNT) and a single walled carbon nanotube (CNT) have been reported. The spectral moment’s method (SMM) was shown to be a powerful tool for determining vibrational spectra (infrared absorption, Raman scattering and inelastic neutron- scattering spectra) of harmonic systems. This method can be applied to...

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  • 2018

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