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Wyszukujesz frazę "67.20.+k" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
The Polaron Scenario for High-T$\text{}_{c}$ Superconductivity
Autorzy:
Ranninger, J.
Powiązania:
https://bibliotekanauki.pl/articles/1860957.pdf
Data publikacji:
1994-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.20.+z
71.38.+i
67.20.+k
Opis:
On the basis of experimental evidence we conclude that high-T$\text{}_{c}$ superconducting materials are composed of two distinct subsystems: one in which electrons are bound together in form of localized pairs of small polarons (bipolarons) and one in which electrons exist as strongly correlated Fermions. Upon doping one passes at a critical doping rate from the insulating parent compounds to metallic compounds. There, a charge transfer mechanism between the two subsystems sets in abruptly by which bipolarons can decay into pairs of electrons and vice versa. Such a picture can be modelled by a mixture of interacting Bosons and Fermions. A superconducting ground state for such a system develops at low temperature which is characterized by the opening of a gap in the single electron spectrum and the appearance of collective Boson excitations with a linear spectrum which is confined to the energy regime of the gap. Above T$\text{}_{c}$, a pseudo-gap remains upon closing the superconducting gap. There are strong indications that the normal state has non Fermi liquid behaviour.
Źródło:
Acta Physica Polonica A; 1994, 85, 1; 89-102
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impurity-Related Linear and Nonlinear Optical Absorption Coefficients of Unstrained (In,Ga)N-GaN Symmetric Coupled QWs
Autorzy:
El Ghazi, H.
John Peter, A.
Powiązania:
https://bibliotekanauki.pl/articles/1399006.pdf
Data publikacji:
2015-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.De
78.20.Ci
42.65.-k
Opis:
Linear, third-order nonlinear and total optical absorption coefficients associated with intra-conduction band in wurtzite unstrained (In,Ga)N-GaN coupled quantum wells are calculated. Based on the effective-mass and the one-band parabolic approximations, the well and the barrier-widths effects are investigated variationally under finite confinement potential barrier. The results indicate that the structure size have a great influence on the optical properties. The results reveal also that larger optical absorption coefficients are obtained compared to single quantum well and a significant red-shift is obtained as the structure size increases. It is found that the modulation of the absorption coefficients can be easily obtained by adjusting the barrier and/or the well widths.
Źródło:
Acta Physica Polonica A; 2015, 127, 3; 787-790
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Second-Order Resonant Polaron in a Self-Assembled Quantum Dot
Autorzy:
Kaczmarkiewicz, P.
Machnikowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/1811933.pdf
Data publikacji:
2008-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.La
78.67.Hc
71.38.-k
63.20.kd
Opis:
We calculate numerically the spectrum of a polaron in a quantum dot in the region of resonance with two-phonon states. We show that the experimental data can be reproduced by a model that does not depend on any adjustable parameters.
Źródło:
Acta Physica Polonica A; 2008, 114, 5; 1139-1144
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural and Spectroscopic Characterization of 1-(5-Bromothiophen-2-yl)-3-(4-nitrophenyl)prop-2-en-1-one: An Analysis of Electronic and NLO Properties
Autorzy:
Tamer, Ö.
Avcı, D.
Atalay, Y.
Powiązania:
https://bibliotekanauki.pl/articles/1204951.pdf
Data publikacji:
2014-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
31.15.E-
33.20.Ea
33.20.Lg
42.65.-k
67.80.Jd
Opis:
The molecular structure of 1-(5-bromothiophen-2-yl)-3-(4-nitrophenyl)prop-2-en-1-one with $C_{13}H_8BrNO_3S$ empirical formula was simulated using B3LYP and CAM-B3LYP levels of density functional theory. After BTNP was optimized on the ground state, its characterization was enhanced via IR, NMR and UV-vis spectroscopies. Conformational analysis was performed based on B3LYP level so as to find the stable conformers of BTNP. Electronic transitions were calculated, and the important contributions from the molecular orbitals to the electronic transitions were investigated. HOMO and LUMO energies were calculated, and obtained energies displayed that charge transfer occurs in BTNP. It was displayed that BTNP is an efficient NLO material due to the coplanar of phenyl-nitro group and carbonyl group. NBO analysis also proved that charge transfer, conjugative interactions and intramolecular hydrogen bonding interactions occur through BTNP.
Źródło:
Acta Physica Polonica A; 2014, 126, 3; 679-687
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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