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Electronic and thermoelectric properties of YbMg_(2)X_(2)(X=P,As,Sb,Bi)zintl compounds by first-principles method

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Journal of Rare Earths 2024年第1期42卷 147-154,I0006页

作者： Sajid Khan Dil Faraz Khan R.Neffati Tariq Usman Muhammad Waqar Ahsraf Shamim Khan Saeed Ullah Jan G.Murtaza department of Physics University of Science&Technology BannuBannu28100Pakistan department of Physics Faculty of ScienceKing Khalid UniversityP.O.Box 9004AbhaSaudi Arabia laboratoire de physique de La Matiere Condensee Departement de PhysiqueFaculte des Sciences de TunisUniversite Tunis El ManarCampus Universitaire1060TunisTunisia department of Physics Shaoxing UniversityShaoxing312000China department of Mathematics&Natural Sciences Prince Mohammad Bin Fahd UniversityAlkhobar31952Saudi Arabia Materials Modeling Lab Department of PhysicsIslamia College Peshawar25120KhyberPakhtunkhwaPakistan

In this work the structural,electronic and thermoelectric properties of YbMg_(2)X_(2)(X=P,As,Sb,Bi)zintl compounds were investigated comprehensively using first principles *** electronic properties were studied using PBE GGA,TB-mBJ and hybrid(YS-PBE0)*** the structural parameters of optimized structures are in harmonious agreement to the available *** band structure study illustrates that the titled materials manifest metallic and semi metallic nature using PBE and TB-mBJ potentials while they show wide band gap semiconducting behavior by following hybrid(YS-PBE0)*** density of states(TDOS)and partial density of states(PDOS)were also calculated to glimpse the contribution of orbitals of atoms in the formation of *** properties were studied by using BoltzTraP2 code employed to *** get enormous values of Seebeck coefficient(S),power factor(PF)and thermoelectric figure of merit(ZT)for all the samples YbMg_(2)X_(2)(X=P,As,Sb,Bi),Moreover,the overwhelming transport properties for the titled compounds indicate the optimum level of carriers’concentration which pinpoints these materials to be better thermoelectrics in the 1-2-2 zintl family.

关键词： Zintl compounds Hybrid functional Band structure Thermoelectrics Rare earths

Influence of isovector pairing and particle-number projection effects on spectroscopic factors for one-pair like-particle transfer reactions in proton-rich even-even nuclei

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Chinese Physics C 2018年第4期42卷 171-187页

作者： Y.Benbouzid N.H.Allal M.Fellah M.R.Oudih laboratoire de physique theorique-faculte de physique-usthb BP32 El-Alia16111 Bab-EzzouarAlgerAlgeria

Isovector neutron-proton（np） pairing and particle-number fluctuation effects on the spectroscopic factors（SF） corresponding to one-pair like-particle transfer reactions in proton-rich even-even nuclei are studied. With this aim, expressions of the SF corresponding to two-neutron stripping and two-proton pick-up reactions, which take into account the isovector np pairing effect, are established within the generalized BCS approach, using a schematic definition proposed by Chasman. Expressions of the same SF which strictly conserve the particle number are also established within the Sharp-BCS（SBCS） discrete projection method. In both cases, it is shown that these expressions generalize those obtained when only the pairing between like particles is considered. First, the formalism is tested within the Richardson schematic model. Second, it is applied to study even-even proton-rich nuclei using the single-particle energies of a Woods-Saxon mean-field. In both cases, it is shown that the np pairing effect and the particle-number projection effect on the SF values are important, particularly in N =Z nuclei, and must then be taken into account.

关键词： neutron-proton pairing particle-number fluctuations spectroscopic factor

Isovector pairing and particle-number fluctuation effects on the spectroscopic factors of one-proton stripping and one-neutron pick-up reactions in proton-rich nuclei

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Chinese Physics C 2018年第8期42卷 137-158页

作者： Y.Benbouzid N.H.Allal M.Fellah M.R.Oudih laboratoire de physique theorique-Facultéde physique-usthb BP32 El-Alia16111 Bab-Ezzouar-Alger-Algeria

Expressions of the spectroscopic factors（SFs） corresponding to one-particle transfer reactions have been established using a schematic *** expressions have been derived by taking into account the isovector neutron-proton（np） pairing correlations and a particle-number projection in the framework of the generalized SharpBCS（SBCS） *** proposed expressions of the projected wave-functions of odd-mass nuclei have been used for this *** formalism has first been tested using the single-particle energies of the schematic picketfence *** is shown that the np pairing and particle-number fluctuation effects are far from negligible and they depend on the pairing gap parameter *** behavior is not the same when the parent nuclei are even-even or *** dealing with the SFs corresponding to one-proton stripping and one-neutron pick-up reactions in proton-rich nuclei have then been established within the framework of the realistic Woods-Saxon *** is shown that the np pairing effect as well as the particle-number projection effect are important and thus have to be included in future calculations of the SF corresponding to these kinds of reactions.

关键词： neutron-proton pairing particle-number projection spectroscopic factor

Boundary States and Correlation Functions of Tricritical Ising Model from Coulomb-Gas Formalism

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Communications in Theoretical Physics 2009年第1期51卷 115-122页

作者： Smain Balaska~* and Toufik Sahabi~+laboratoire de physique theorique d’Oran, departement de physique, Universite d’Oran Es-Senia, 31100 Es-Senia,Algeria. laboratoire de physique theorique d"Oran Departement de Physique Universite d"Oran Es-Senia

We consider the minimal conformal model describing the tricritical Ising model on the disk and on theupper half plane. Using the coulomb-gas formalism we determine its consistents boundary states as well as its one-po... 详细信息

关键词： boundary conformal field theory tricritical Ising model boundary states and Coulomb-gas formalism

Dynamics of Super Quantum Correlations and Quantum Correlations for a System of Three Qubits

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Communications in Theoretical Physics 2016年第4期65卷 447-452页

作者： F.Siyouri M.El Baz S.Rfifi Y.Hassouni laboratoire de physique theorique Departement de Physique Faculte des sciences Universite Mohammed V - AgdalAv. Ibn Battouta B.P. 1014 Agdal Rabat Morocco

The dynamics of quantum discord for two qubits independently interacting with dephasing reservoirs have been studied *** authors [***.A 88(2013) 034304] found that for some Bell-diagonal states(BDS)which interact with their environments the calculation of quantum discord could experience a sudden transition in its dynamics,this phenomenon is known as the sudden *** in the present paper,we analyze the dynamics of normal quantum discord and super quantum discord for tripartite Bell-diagonal states independently interacting with dephasing ***,we find that basis change does not necessary mean sudden change of quantum correlations.

关键词： super quantum discord normal quantum discord Bell-diagonal states measurement strength

Auto-correlation Effects on the sp^3-d Exchange Interaction in Cd1-x MnxTe/CdTe Multilayers

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Chinese Physics Letters 2002年第11期19卷 1679-1682页

作者： K. Afif A. Benyoussef J. Diouri laboratoire de Magnetisme Faculte des Sciences Groupe d"Electronique et de physique du Solide Faculte des Sciences

Band offsets and total energy of wannier excitons in multilayers are affected by dimensional and auto-correlation effects, sp3-d coupling is consequently modified. Thus, the calculation of the Zeeman splitting in the quantum wells has to take into account these effects, especially when the mismatch cannot be disregarded. In this work, theoretical study of these combined effects has been performed for Cd1-xMnxTe/CdTe multilayers embedded by Cd1-yZnyTe as the substrate (or the buffer) on one side and as a cladding layer in the other side. This sample allows us to highlight the role played by the substrate (buffer) and the growth direction on the Zeeman splitting in such multilayers.

关键词： Multilayers

Surface Effects on Wannier Excitons in Superlattices:Monte Carlo Simulation

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Chinese Physics Letters 2002年第8期19卷 1164-1167页

作者： K. Afif A. Benyoussef J. Diouri laboratoire de Magnetisme Faculte des Sciences Groupe d"Electronique et de physique du Solide Faculte des Science

Using a Monte Carlo quadrature, we calculate by a variational method the binding energy Eb of wannier excitons in N-periods m-CdMnTe/n-CdTe superlattices, including or not including the step discontinuity in the potential barrier at the interface, and with varying N as well as well-width. The calculation is performed in the framework of the effective mass approximation for both heavy-hole and light-hole excitons. The degree of excitonique localisation dependence on those parameters is accurately illustrated.

关键词： Monte Carlo methods

Mid/far-infrared photo-detectors based on graphene asymmetric quantum wells

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Chinese Physics B 2016年第9期25卷 573-580页

作者： E Ben Salem R Chaabani S Jaziri Institut Preparatoire aux Etudes d'Ingenieurs de Tunis 2 Rue Jawaher Lel Nahrou Monfleury 1089 Tunisie laboratoire de physique de la Matiere Condensee Departement de Physique Faculte des Sciences de Tunis Campus Universitaire 2092 Tunisie departement de physique Faculte des Sciences de Bizerte Jarzouna 7021 Bizerte

We conducted a theoretical study on the electronic properties of a single-layer graphene asymmetric quantum *** of energy levels is limited by electron–hole conversion at the barrier interfaces and free-electron ***–hole conversion at the barrier interfaces can be controlled by introducing an asymmetry between barriers and taking into account the effect of the interactions of the graphene sheet with the *** interaction with the substrate induces an effective mass to carriers,allowing observation of Fabry–P′erot resonances under normal incidence and extinction of Klein *** asymmetry,between barriers creates a transmission gap between confined states and free-electron continuum,allowing the large graphene asymmetric quantum well to be exploited as a photo-detector operating at mid-and far-infrared frequency regimes.

关键词： graphene quantum wells reflection coefficient photo-detector

Structural,electronic,optical,and magnetic properties of Co-doped Cu2O

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Chinese Physics B 2017年第2期26卷 387-391页

作者： I Djabri T Rezkallah F Chemam laboratoire de la physique Appliquee et theorique Departement des Sciences de la matiere Universite Laarbi tebessi tebessa Algeri

We investigate the magnetic properties of Co-doped Cu_2O. We studied first the electronic and structural properties of Cu_2O using the optimization of the lattice constant which is 4.18 . The calculated gap is found between 0.825 eV and1.5 eV, these values are in good agreement with the experimental results. The Co atoms are inserted in Cu_2O by means of the density functional theory（DFT） using LSDA, LSDA ＋U, and LSDA ＋ MBJ approximations in the WIEN2 k code, based on the supercell model by setting up 12, 24, and 48 atoms in（1×1 × 2）,（1 × 2 × 2）, and（2 × 2×2） supercells respectively with one or two copper atoms being replaced by cobalt atoms. The energy difference between the ferromagnetic and antiferromagnetic coupling of the spins located on the substitute Co has been calculated in order to obtain better insight into the magnetic exchange coupling for this particular compound. The studied compound exhibits stable integer magnetic moments of 2 μBand 4 μBwhen it is doped with 2 atoms of Co. Optical properties have also been worked out. The results obtained in this study demonstrate the importance of the magnetic effect in Cu_2O.

关键词： Cu2O electronic structure magnetic properties optical properties