Mutual modification of silver-nanoparticle plasmon resonances and the absorptive properties of polymethine-dye molecular layers on a sapphire surface

Extinction spectra of a hybrid material comprised of molecular layers of polymethine dyes and granulated silver films preliminarily deposited onto sapphire substrates are studied experimentally. Specific features of the dye layer composition and broadening of plasmon absorption bands are discussed. In hybrid samples, both an increase and a decrease in the silver-nanoparticle plasmon resonance frequency upon spreading of dyes have been observed, as well as a considerable increase in the dye molecule absorption. Possible mechanisms of the phenomena are discussed.     

Effect of an in-plane magnetic field on magnetoresistance hysteresis of the two-dimensional electron gas in the integer quantum Hall effect regime

Effect of an in-plane magnetic field on the features of the magnetoresistance of a narrow conducting channel placed in the bath of a macroscopic two-dimensional electron gas has been studied. These features are manifested in the hysteretic behavior of the magnetoresistance in the quantum Hall effect regime. It has been found that the hysteresis loops observed in different ranges of the filling factor may be separated into two groups that differ in both the response to the in-plane magnetic field and the temperature dependence. The basic features observed near the integer filling factors ν = 1 and 2 are almost independent of the in-plane magnetic field. Therefore, their origin is not associated with spin effects. At the same time, additional features that appear at ν ≈ 1.8 and 2.2 are suppressed by the in-plane magnetic field B _‖ ≈ 6 T and almost temperature-independent from 45 mK to 1 K.     

Photovoltaic effect in submicron ballistic rings

Photovoltaic effect is investigated for ballistic AlGaAs/GaAs rings under microwave radiation. The comparison of microwave EMF versus magnetic field dependencies and magnetoresistance shows that in ballistic rings the photovoltaic effect is due to the absence of central symmetry in microstructure geometry.     

Forward Raman scattering in GaAs/AlAs superlattices: Study of optical phonon anisotropy

We present the forward Raman scattering study of zone-centre optical phonon anisotropy in short-period GaAs/AlAs superlattices. Experiments were performed on specially prepared superlattice structures having anti-reflection dielectric coatings and removed substrates. The experimental data are compared with the angular dispersion of superlattice optical phonons calculated within the dielectric susceptibility model. We have found a good agreement between the experimental data and the calculations taking into account interface disorder. Received 9 September 1998 and Received in final form 22 October 1998     

Effects of gas flow speed and chlorine concentration on tellurium uptake in gas-phase epitaxy of gallium arsenide

A comparison is made between the growth kinetics of gallium arsenide films and the uptake of tellurium in gas-phase epitaxy in a chlorine system. The ratelimiting stages for both processes are the same and are associated with diffusion through the boundary layer and the rates of surface processes (adsorption and desorption).Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 18–21, November, 1982.We are indebted to A. I. Saprykin for performing the mass spectrometry of the gallium arsenide films.     

Thermodynamic system far from equilibrium. II. Supersymmetric method for the φ4-model

We have used second-order perturbation theory to derive expressions for the supersymmetric components of the self-energy parts of a superfield propagator.Sumskii Physico-Technical Institute, Scientific-Industrial Enterprise of the RETO. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 39–42, August, 1994.