排序方式: 共有8条查询结果,搜索用时 15 毫秒
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Shijun Liang Wenfang Xie H.A. Sarkisyan A.V. Meliksetyan Huaya Shen 《Superlattices and Microstructures》2012
Optical properties of a nanoring with Winternitz–Smorodinsky confinement potential in the presence of an external magnetic field have been studied theoretically. Our results demonstrate that energy, oscillator strength and the linear, nonlinear and total absorption are strongly affected by size of the nanoring. Also, we found that magnetic field has little influence on energy difference, oscillator strength and optical absorption of the nanoring. 相似文献
2.
R Nirmala V Sankaranarayanan K Sethupathi AV Morozkin T Geethakumary Y Hariharan 《Pramana》2002,58(5-6):1101-1104
New R
2Ti3Ge4 (R=Dy, Ho and Er) intermetallic compounds have been synthesized and characterized by X-ray diffraction and low temperature ac
magnetic susceptibility, electrical resistivity and thermoelectric power measurements were carried out. The compounds crystallize
in the parent, Sm5Ge4-type orthorhombic structure (space group Pnma) and lanthanide contraction is observed as one moves along the rare-earth series.
The changeover from paramagnetic to antiferromagnetic phase happens at low temperatures and the ordering temperature scales
with the de Gennes factor. The electrical resistivity is metallic with a negative curvature above 100 K. Thermopower displays
a weak maximum at temperatures less than 50 K signifying the possible phonon and magnon drag effects. 相似文献
3.
A. K. Atayan E. M. Kazaryan A. V. Meliksetyan H. A. Sarkisyan 《Journal of Contemporary Physics (Armenian Academy of Sciences)》2010,45(3):126-131
We investigate magnetoexcitonic states in the Ga1−x
1Alx
1As/GaAs/Ga1−x
2Alx
2 As quantum ring with the Winternitz-Smorodinsky confinement potential. A homogeneous magnetic field is directed perpendicularly
to the ring plane. The Coulomb interaction between the electron and hole is assumed as weak and is considered in the framework
of perturbation theory. Obtained results show that the more realistic Winternitz-Smorodinsky confinement potential, which
takes into account a peculiar smoothing of the confinement potential profile, leads to raising of the electron energy levels
as compared to the case of a finite-height rectangular confinement potential. 相似文献
4.
A. K. Atayan E. M. Kazaryan A. V. Meliksetyan H. A. Sarkisyan 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,63(4):485-492
The absorption of light in an ensemble of non-interacting cylindrical quantum dots in the presence of a magnetic field is
discussed using a model consisting of dots with rectangular infinitely-high potential barriers. The ensemble’s absorption
coefficient is calculated — as well as the threshold frequency of absorption — as a function of the applied magnetic field
and the quantum dot size. Theoretical results are compared with experimental data on magneto-luminescence in an In0.53Ga0.47As/InP cylindrical quantum dot system. In addition, using a perturbation theory framework, the influence of excitonic effects
on the behaviour of the electron-hole energetic spectrum of said system is discussed. 相似文献
5.
Resonant ultrasound spectroscopy was used to measure the elastic constants of bcc Ta0.33V0.67 over the temperature range 3.5–300?K; the results were compared to earlier measurements on C15 TaV2. The temperature dependence of the polycrystalline shear modulus is completely different in the two phases; that of the bcc phase decreases with temperature whereas that of the C15 phases increases in an anomalous fashion. This difference is consistent with a model involving doubly-degenerate levels at the X point of the Brillouin zone in the C15 phase with the Fermi level lying near the doubly degenerate level. This model accounted for the unusual behaviour of the C15 phase. Debye temperatures were determined from the ultrasonic measurements: 295?K for the C15 phase and 315?K for the bcc phase. 相似文献
6.
We have studied the nonlinear optical absorption and the nonlinear optical rectification of an exciton in a nanoring in the presence of magnetic flux. The calculation results show that one can control the properties of nonlinear optical absorption and nonlinear optical rectification of a nanoring by tuning the outer and inner radius. Moreover, we find that the nonlinear optical properties of a nanoring can be modulated by the magnetic flux through the nanoring. 相似文献
7.
E.M. Kazaryan A.V. Meliksetyan L.S. Petrosyan H.A. Sarkisyan 《Physica E: Low-dimensional Systems and Nanostructures》2006,31(2):228-231
The impurity states in a narrow-gap semiconductor parabolic quantum dot in the presence of external extremely strong magnetic field are considered in adiabatic approximation framework. Moreover, the dispersion law for impurity electron is described by using the Kane's two-band approximation. The effective one-dimensional equation describing the impurity electron's state along the field is obtained. The analytical expressions for total and binding energies of impurity ground state are obtained. The dependences of total and binding energies of impurity on the value of magnetic field and on the size of quantum dot are investigated. 相似文献
8.
V.M. Arutunyan G.P. Djotyan A.V. Karmenyan T.E. Meliksetyan 《Optics Communications》1984,52(2):114-116
A simple method to amplify laser radiation is proposed: the divergence is nearly diffraction limited and the intensity distribution profile is gaussian (independent of the spatial parameters of the input signal). The amplification of the laser radiation is achieved using the quasi-waveguide laser of a solution of rhodamin 6G with a concentration of 10-2 mol/. A hundred fold intensity amplification with a divergence of 6 × 10-4 rad is achieved, the latter being only 1.4 times more than the diffraction limited divergence of the system. 相似文献
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