Influence of the magnetic field and measurement temperature on the shape of microphotoluminescence spectra of Eu-Doped InGaN/GaN quantum-well structures

Based on the results of complex investigations of the influence of the magnetic field strength and measurement temperature on the shape of microphotoluminescence (micro-PL) spectra of Eu-doped InGaN/GaN quantum-well structures, the determination of the charge state of Eu impurity ions, and the change in the concentration of dopant ions, it has been shown that an increase in the magnetic field strength (0–5 T) leads to a more significant decrease in the luminescence intensity as compared to the undoped structures. An increase in the measurement temperature from 4.2 to 78 K results in an enhancement of the effect of the magnetic field on the shape of the micro-PL spectra of Eu-doped InGaN/GaN structures. It has been demonstrated that the doping of InGaN/GaN quantum-well structures with europium at a high excitation level leads to a shift in the maximum of the luminescence intensity toward the long-wavelength range of the spectrum.     

Diagram technique for the Hubbard model

Institute of Applied Physics, Moldavian SSR Academy of Sciences. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 82, No. 3, pp. 428–437, March, 1990.     

Perturbation theory for the periodic Anderson model

We investigate the system of conductivity electrons and f-localized electrons described by the periodic Anderson model. Single-site hybridization of the state of two constituent subsystems of electrons is treated as a perturbation. We develop a new diagram technique based on the use of multiparticle one-site irreducible Green’s functions for the f-electrons and the standard Wick theorem for the subsystem of conductivity electrons. We derive the Dyson equations for the one-particle Green’s functions and find the relation between these functions. These results are exact and can be used as a starting point for self-consistent approximations. In the Hubbard-I approximation, we analyze the spectrum of one-particle perturbations. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 110, No. 2, pp. 308–322, February, 1997.     

Polymethine dyes from isomeric 2-methylthionaphthenothiazoles

A number of quino (2)monomethylidyne-, carbo-, mero-, dimero-, and rhodacyanines (thieno[3,2-e]benzothiazole derivatives) were synthesized. It is shown that replacement of the vinylene group by a sulfur atom in one of the benzene rings of the naphtho[1,2-d]thiazole residues in the cyanines and merocyanines does not affect the positions of their absorption maxima.See [1] for communication IV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1189–1192, September, 1972.