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Barseghyan M.G.,Yerevan State University | Barseghyan M.G.,National University of Architecture and Construction of Armenia
Physica E: Low-Dimensional Systems and Nanostructures | Year: 2015

A detailed investigation of the lateral electric field effect on single electron states in coupled quantum dot-ring structure has been systematically studied for cases with and without an on-center hydrogenic donor impurity. The single electron energy spectrum has been found using the effective mass approximation and an exact diagonalization technique. The electron ground state's probability density has been examined for different values of the confinement energies and depth of dot confinement relative to the bottom of the quantum ring and barrier thickness. The energy level's dependence on the electric field strength has been studied considering the effects of mentioned parameters of the structure and hydrogenic donor impurity. © 2015 Elsevier B.V. All rights reserved. Source


Hakobyan S.N.,State Engineering University of Armenia | Shahinyan M.A.,Yerevan State University | Babayan Y.S.,National University of Architecture and Construction of Armenia
Biophysical Reviews and Letters | Year: 2016

In the present work, the thermostabilities of mitoxantrone (MTX) complexes with DNA from sarcoma 45 and healthy rat liver were studied. DNAs from both sources were irradiated by resonant (64.5 GHz and 50.3 GHz) and nonresonant (48.3 GHz) frequencies of water. The obtained data showed that DNA solution irradiation by resonant frequencies of water induces a dehydration of nucleotides and Na(Formula presented.) ions in the solution. It is shown that at relatively low concentrations of MTX, when one MTX molecule binds to almost 100 pairs of bases of DNA, the thermostabilities of complexes decrease. Moreover, this change is more pronounced ((Formula presented.)C) at the complex formation with DNA released from sarcoma 45 tumor. © 2016 World Scientific Publishing Company Source


Barseghyan M.G.,Yerevan State University | Barseghyan M.G.,National University of Architecture and Construction of Armenia
Optics Communications | Year: 2016

The intraband optical absorption in GaAs/Ga0.7Al0.3As two-dimensional single quantum ring is investigated. Considering the combined effects of hydrostatic pressure and intense laser field the energy of the ground and few excited states has been found using the effective mass approximation and exact diagonalization technique. The energies of these states and the corresponding threshold energy of the intraband optical transitions are examined as a function of hydrostatic pressure for the different values of the laser field parameter. We also investigated the dependencies of the intraband optical absorption coefficient as a function of incident photon energy for different values of hydrostatic pressure and laser field parameter. It is found that the effects of hydrostatic pressure and intense laser field lead to redshift and blueshift of the intraband optical spectrum respectively. © 2016 Elsevier B.V. Source


Baghramyan H.M.,University of Tarapaca | Barseghyan M.G.,Yerevan State University | Barseghyan M.G.,National University of Architecture and Construction of Armenia | Laroze D.,University of Tarapaca | And 2 more authors.
Physica E: Low-Dimensional Systems and Nanostructures | Year: 2016

The influence of lateral electric field on one-electron states and intraband absorption in two-dimensional concentric double quantum rings is investigated. The confining potential of the rings is modeled as a double harmonic central potential. Using the exact diagonalization technique, we calculate the dependence of the electron energy spectrum as a function of the electric field strength as well as the inner ring radius. Also, different values of confinement strength are considered. Selection rule is obtained for intraband transitions, caused by the direction of incident light polarization. The intraband absorption coefficient is calculated for different values of electric field strength, inner ring radius, confinement strength and incident light polarization direction. The combined influence of electric field strength and change of confining strength show that while the increment of the first one leads only to blueshift of absorption spectrum, the augment of the second one makes the redshift. In addition, both blueshift and redshift of the spectrum have been obtained with the enlargement of inner ring radius. Finally, we show that the absorption spectrum undergoes redshift by changing the polarization of incident light from x- to y-axis. © 2015 Elsevier B.V. Source


Radu A.,Polytechnic University of Bucharest | Kirakosyan A.A.,Yerevan State University | Laroze D.,University of Tarapaca | Laroze D.,University of Glasgow | And 2 more authors.
Semiconductor Science and Technology | Year: 2015

The simultaneous influences of an intense laser field and static electric field on one-electron states and intraband optical absorption coefficient are investigated in two-dimensional GaAs/Ga0.7Al0.3 As quantum ring. An analytical expression of the effective confining potential in the presence of the external fields is obtained. The one-electron energy levels and wave functions are calculated using the effective mass approximation and an exact diagonalization technique. We show that changes in the incident light polarization lead to blue- or redshifts in the intraband optical absorption spectrum. Moreover, we found that blueshift and redshift are induced by the simultaneous influences of an intense laser and lateral electric fields. The obtained theoretical results indicate a novel opportunity to tune the performance of quantum rings and to control their specific properties by means of intense laser and homogeneous electric fields. © 2015 IOP Publishing Ltd. Source

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