The transmission probability of quasi-particles in an ultra-cold superfluid contained two channels: the effects of size of system, within the BCS quasi-classical approximation
ندا
ابراهیمیان
هیات علمی- دانشگاه شاهد
author
text
article
2016
per
Of central importance in ultra-cold Fermi superfluids contained two channels with different energies, is the study of effects of size of system on different physical parameters. One of the important parameters in these systems is the interface transmission probability between superfluid and normal phases. In this paper, by using the Bogoliubov equations and the first order perturbation for two channels and also by considering the approximation related to deep BCS region for quasi-particles momentum and quasi-holes momentum, the effects of size of system, which is expressed within the quasi-classical approximation, are calculated on interface transmission coefficient of two channels of ultra-cold system and the physical diagrams are separately plotted and compared.
Journal of Research on Many-body Systems
Regional Information Center for Science and Technology (RICeST)
2322-231X
6
v.
ویژه نامه شماره 2
no.
2016
1
10
http://jrmbs.scu.ac.ir/article_12511_5453da1cc51b55573711021932c6142a.pdf
dx.doi.org/10.22055/jrmbs.2016.12511
Computational and Theoretical Study of Electronic, Spectroscopic and Chemical Properties of (ZnO)n (n≤4) nanoclusters
Razieh
Habibpour Gharacheh
Assistant Professor/Iranian Research Organization for Science and Technology
author
Raheleh
Vaziri
مدرس/دانشگاه پیام نور
author
text
article
2016
per
In this article; structural stability, electronic and spectroscopic properties of zinc oxide nanoclusters up to four atoms are studied by hybrid Density Functional Theory. The stable structures of these nanoclusters have been fully optimized with Gaussian 09W program package at B3LYP/LanL2DZ level. The vibrational frequencies, IR intensities, binding energy, HOMO–LUMO energy gap, symmetry, and dipole moment are also computed for the most stable isomer of each cluster. The reactivity descriptors such as electronegativity, chemical hardness and softness index of the lowest-energy isomers are estimated for these nanoclusters to study their relative stabilities. (ZnO)4/2 isomer has the most reactivity, because it is the softest and most unstable isomer.
Journal of Research on Many-body Systems
Regional Information Center for Science and Technology (RICeST)
2322-231X
6
v.
ویژه نامه شماره 2
no.
2016
11
20
http://jrmbs.scu.ac.ir/article_12472_aa5eff8a4f29e5c092d0700f3277a992.pdf
dx.doi.org/10.22055/jrmbs.2016.12472
Transport in quantum dots resonant tunneling diodes
Mohammadtaghi
Asefpour
Dept Physics, Isfahan University of Technology
author
پیمان
صاحب سرا
دانشگاه صنعتی اصفهان
author
text
article
2016
per
In this paper, we simulate a resonant tunneling diode (RTD). Using Green's function method for the tight-binding approximation, we calculate local density of states and current-voltage characteristic by the Green function components of the system. Results show a non-Ohmic behavior and negative differential resistance in RTD. As a result of a longitudinal electric field, the local density of states varies by changing the applied potential. Moreover, we study the effect of changing the physical parameters on the current of the device. Entering quantum dots in the middle of device causes a negative differential resistance, which is a consequence of resonant tunneling phenomenon.
Journal of Research on Many-body Systems
Regional Information Center for Science and Technology (RICeST)
2322-231X
6
v.
ویژه نامه شماره 2
no.
2016
21
25
http://jrmbs.scu.ac.ir/article_12473_9b83299945f6373b700f435e87e8b8d7.pdf
dx.doi.org/10.22055/jrmbs.2016.12473
Investigation of structural , electronic and phononic properties of InN in wurtzite
nadia
navaser
student/shahid chamran university
author
حمدا..
صالحی
دانشگاه شهید چمران
author
پیمان
امیری
دانشگاه شهید چمران اهواز
author
text
article
2016
per
In this paper the structural, electronic and phononic properties of InN in a wurtzite structure have been studied. The calculations have been performed using a pseudoptential method in the framework of Density Functional Theory (DFT) by PWscf package with LDA, GGA and PBE0 approximations for the exchange and correlation potential terms. Calculated band gap for InN in the hexagonal phase is equal to 2.2 eV at the point. The mostly contributed in the valence band and in conduction band of the s-orbital nitrogen atom and orbital s and p indium atoms. The phonon spectrum shows a frequency gap in 209.885 to 453.112 cm-1 that in this range will have complete reflection.
Journal of Research on Many-body Systems
Regional Information Center for Science and Technology (RICeST)
2322-231X
6
v.
ویژه نامه شماره 2
no.
2016
27
32
http://jrmbs.scu.ac.ir/article_12474_64fa16c2e50ec9093789a62498079927.pdf
dx.doi.org/10.22055/jrmbs.2016.12474
Calculation the electronic structure of KNbO3 in cubic phase by using Full Potential-Linearized augmented plan wave method
حمداله
صالحی
دانشگاه شهید چمران اهواز
author
zohre
javdani
دانشگاه شهید چمران اهواز
author
text
article
2016
per
In this paper the electronic structure of KNbO3 such as lattice constant, bulk modulus, the first pressure derivative of the bulk modulus and Compressibility have been studied. The calculations have been performed using a Full Potential-Linearized Augmented Plane Wave (FP-LAPW) method in the framework of Density Functional Theory (DFT) by WIEN2k package with LDA, GGA96، GGA91 approximations for the exchange and correlation potential terms. Calculated band gap for KNbO3 in the best approximation is equal to 2.21 eV for direct and 1.42 eV for indirect. The results show that the calculation using by GGA approximation has the better agreements with the other theoretical and experimental approximations.
Journal of Research on Many-body Systems
Regional Information Center for Science and Technology (RICeST)
2322-231X
6
v.
ویژه نامه شماره 2
no.
2016
33
39
http://jrmbs.scu.ac.ir/article_12475_00e90ed2592ac113f20d2aad91250482.pdf
dx.doi.org/10.22055/jrmbs.2016.12475
The effect of interaction on temperature behavior of the polarization and the anomalous self-energy for hole-doped and electron-doped cuprates
رضا
افضلی
عضو هیات علمی دانشکده فیزیک دانشگاه صنعتی خواجه نصیرالدین طوسی
author
عمید
علی زاده
دانشکده فیزیک دانشگاه صنعتی خواجه نصیرالدین طوسی
author
text
article
2016
per
By considering the spin-fermion model that uses spin fluctuations as mechanism for pairing in HTSCs, we calculate the spin susceptibility or the polarization for hole-doped and electron-doped cuprates. For constant gap, we calculate a part of procedure analytically. In momentum dependent gap we presented polarization in term of frequency at zero temperature firstly and then considering discrete frequencies, we investigate the finite temperature case. Also considering a non-linear equation for superconducting gap, the first order approximation of energy gap in terms of momentum and frequency is represented. Finally, using self-consistent Eliashberg equations, we calculate first order self-energy for electron-doped and hole-doped cuprates and the effect of interaction is investigated
Journal of Research on Many-body Systems
Regional Information Center for Science and Technology (RICeST)
2322-231X
6
v.
ویژه نامه شماره 2
no.
2016
41
49
http://jrmbs.scu.ac.ir/article_12476_5a8224bc5a3b9c7832170aed61453432.pdf
dx.doi.org/10.22055/jrmbs.2016.12476
Josephson Effect in Two-Gap Iron-Based Superconductors
Mohammad Ali
Maleki
Faculty member / University of Zanjan
author
Ali
Ghorbanzadeh Mogaddam
Faculty member / Institute for Advanced Studies in Basic Sciences - Zanjan
author
Mitra
Taherkhani
Student / University of Zanjan
author
text
article
2016
per
The Josephson effect is studied in SIS junctions made of two band reversed sign s-wave superconductors. The insulator region I is considered to have finite thickness. The solutions of the Bogoliubov de genes equation are considered in two superconducting regions and also in intermediate insulator region. Then, the appropriate boundary value conditions are applied on the wave functions. An eigenvalue equation is obtained for the energy spectrum which depends on a few parameters of the problem, like the thickness of the insulator region. For some special values for parameters of the problem, changing the thickness of the insulator region, a zero-pi phase transition is observed.
Journal of Research on Many-body Systems
Regional Information Center for Science and Technology (RICeST)
2322-231X
6
v.
ویژه نامه شماره 2
no.
2016
51
55
http://jrmbs.scu.ac.ir/article_12477_fa39084b6effb624881d88a7c1ac2d2a.pdf
dx.doi.org/10.22055/jrmbs.2016.12477
The effect of vacancies on magnetic properties of armchair graphene nanoribbons
Ebrahim
Keshavarz Safari
Bu-Ali Sina University
author
Manouchehr
BabaeiPour
Department of Physics, Bu-Ali Sina University, Hamedan
author
Ali Asghar
Shokri
Department of Physics, Payame Noor University, Tehran
author
text
article
2016
per
In the absence of lattice defects, pristine graphene and hydrogen-terminated armchair graphene nanoribbons are non-magnetic materials. The presence of vacancies extremely effect on the magnetic properties and they can produce remarkable spin polarization in these materials. In this study, using first principles calculations based on Kohn-Sham density functional theory (KS-DFT), the effect of the presence of vacancies on magnetic properties and spin polarization of monolayer and bilayer armchair graphene nanoribbons are investigated. The results show that the magnitude of magnetic moments depends on the number and configuration of vacancies, their distance from each other as well as from nanoribbons' edges.
Journal of Research on Many-body Systems
Regional Information Center for Science and Technology (RICeST)
2322-231X
6
v.
ویژه نامه شماره 2
no.
2016
57
63
http://jrmbs.scu.ac.ir/article_12478_5add8dc6437f9a7fd0ed8f7a50b50ef2.pdf
dx.doi.org/10.22055/jrmbs.2016.12478
Study of electronic structures, magnetic properties and magic numbers in small iron clusters: A spin-polarized density functional study
مهناز
محمدی
هییت علمی
author
لیلا
علی چراغی
دانشجو
author
بهرام
خوشنویسان
هییت علمی
author
text
article
2016
per
Spin-polarized Density functional calculations with the generalized gradient approximation (GGA) were employed for a systematic study of electronic structures, magnetic properties and magic numbers of Fe_n aggregates with n ≤9 atoms. The results show that the magnetic moment of per atom in each nano-cluster is higher than those of their bulk material magnetic moment. In generally, our results show that the magnetic moment per atom of the nano-clusters growth with the size of the clusters. In addition, the average binding energy increases monotonically with the increase of n and become comparable to the bulk values. Nano cluster with 7 atoms is the first magic number and this result is in good agreement with the experimental reports and on the other hand show that the approximations are proper. The study suggests that such Fe nano-clusters may be useful in biomedical and spintronic.
Journal of Research on Many-body Systems
Regional Information Center for Science and Technology (RICeST)
2322-231X
6
v.
ویژه نامه شماره 2
no.
2016
65
72
http://jrmbs.scu.ac.ir/article_12479_47708bd3bbd18c2d02e01dc1bd487ae7.pdf
dx.doi.org/10.22055/jrmbs.2016.12479
Investigation of structural, electronic and magnetic properties of Sr2NiWO6 double perovskite using ab initio calculations
طیبه السادات
هاشمی فر
گروه فیزیک، دانشکده علوم پایه، دانشگاه شهرکرد، شهرکرد
author
Ali
Mokhtari
هیئت علمی
author
text
article
2016
per
Double perovskites have been found to be very interesting material among researchers since they exhibit a wide variety of physical properties. In this paper the Sr2NiWO6 double perovskite was studied using ESPRESSO package within the framework of Density Functional Theory (DFT). According to experimental results this perovskite is an insulator and has a band gap about 3.1 eV. After structural optimization, in first step, electronic properties of compound were calculated using generalized gradient approximation (GGA) and strong correlation correction (GGA+U) with different values of Hubbard parameter (U). The optimum value of the U parameter was chosen using results of strong correlation correction and available experimental data in next step. Finally, the stable magnetic phase of Sr2NiWO6 between paramagnetic, ferromagnetic and anti-ferromagnetic phases was studied using optimized Hubbard parameter.
Journal of Research on Many-body Systems
Regional Information Center for Science and Technology (RICeST)
2322-231X
6
v.
ویژه نامه شماره 2
no.
2016
75
82
http://jrmbs.scu.ac.ir/article_12480_412bd80b4af5ffb985ad6ff924402fd2.pdf
dx.doi.org/10.22055/jrmbs.2016.12480
Investigation of Structural and magnetic properties of graphene Nanoribbons doped with Fe atoms
Parvin
Zanganeh
دانشجو
author
طیبه
مولاروی
عضو هیئت علمی- گروه فیزیک- دانشگاه صنعتی شاهرود
author
text
article
2016
per
In this paper, the stability, electronic and magnetic properties of rapheme nanoribbons with zigzag edge shape (ZGNR) doped by Fe atoms, using density functional theory (DFT) have been investigated. According to our investigations and obtained values for the formation and binding energy, the best situation for the substitution Fe atoms by carbon atoms found at the edge of ZGNR and with the carbon atoms which are bonded to the hydrogen atoms. Also if Fe atoms substituted to Hydrogen atoms instead of carbon atoms, the structure would be more energy desirable and when the structure doped by two Fe atoms in both ferro and anti ferromagnetic phases, close doping is more stable than far doping. The maximum magnetic moment is found about 5 B for Fe doping when substituted to Hydrogen atoms in F site. According to the electronic band structure calculations, the electronic and magnetic properties of ZGNR depend to situation of substituted Fe atoms and depending on what location were choose to replace the iron atoms, magnetic metal or magnetic semiconductors will be achieved.
Journal of Research on Many-body Systems
Regional Information Center for Science and Technology (RICeST)
2322-231X
6
v.
ویژه نامه شماره 2
no.
2016
83
91
http://jrmbs.scu.ac.ir/article_12481_16f63e99deb6e56d77456c4d63db134a.pdf
dx.doi.org/10.22055/jrmbs.2016.12481
Statistical study of two-dimensional electron gas within Thomas-Fermi approximation
morteza
NattaghNajafi
هیئت علمی
author
Hossein
Mohammadzadeh
هیئت علمی دانشگاه
author
text
article
2016
per
In this paper we consider the two-dimensional electron gas. To this end we first take into account the electronic coherence length and consider the system as some cells with linear lengths equal to the coherence length. Inside these cells we have an interactive electron gas and outside them we consider a semi-classical dynamics. We obtain the energy functional of the gas inside the cells within the Thomas-Fermi-Dirac approximation and use classical Monte Carlo scheme to investigate the inter-cell dynamics. After each electron injection we let the system to become equilibrated. After these steps we analyze geometrically and algebraically the statistical observables of the system. The most important observation is the decreasing behavior of the energy of the system in terms of temperature in some regions showing the instability of the electron gas in these regions.
Journal of Research on Many-body Systems
Regional Information Center for Science and Technology (RICeST)
2322-231X
6
v.
ویژه نامه شماره 2
no.
2016
93
99
http://jrmbs.scu.ac.ir/article_12482_7fc8f233fa9ef570a5bf1145d42e59a9.pdf
dx.doi.org/10.22055/jrmbs.2016.12482
Investigation of charge and magnetic states of Fe atom doped rutile TiO2
مهدی
واعظ زاده
دانشگاه صنعتی خواجه نصیرالدین طوسی
author
عادله
مخلص گرامی
دانشگاه صنعتی خواجه نصیرالدین طوسی
author
text
article
2016
per
The structural and magnetic properties of Fe doped rutile TiO2 is calculated using density function theory. In order to study the different charge states of Fe, and their role in the magnetic properties as well, the various configurations of Fe are considered. Moreover, the effect of oxygen vacancy on electronic structure of each configuration is investigated. The results corresponding to the density of state energy in the configuration of interstitial Fe with oxygen vacancy show that the charge state of Fe is 2+. Furthermore, by changing the distance between vacancy oxygen and substantial Fe at Ti site, the effect of crystalline structures on other possible charge states of Fe are discussed. In order to shed light on charge states of Fe by its location on lattice, the hyperfine parameters of isomer shift and quadrupole splitting are calculated, and the results are compared with available experimental Mössbauer results for Fe2+ and Fe3+ charge states.
Journal of Research on Many-body Systems
Regional Information Center for Science and Technology (RICeST)
2322-231X
6
v.
ویژه نامه شماره 2
no.
2016
101
109
http://jrmbs.scu.ac.ir/article_12483_ef38dd0019213f40cfa2598461e648da.pdf
dx.doi.org/10.22055/jrmbs.2016.12483