Observation of the interaction between Landau levels of different two-dimensional subbands in GaAs in a normal magnetic field

Tunnel current measurements between strongly disordered two-dimensional electron systems in a perpendicular magnetic field are presented. Two-dimensional electron accumulation layers are formed by an extremely narrow layer of Si donors (Si delta doping) in GaAs on either side of an AlGaAs tunnel barrier. Strong interaction between Landau levels of the two-dimensional subbands in each accumulation layer is observed as an anticrossing of the related peak positions in the tunnel current vs. voltage curves as a function of magnetic field. The splitting of the interacting Landau levels is about 10 meV, which cannot be explained by nonparabolicity of the conduction band in GaAs. A possible reason for the observed interaction connected with the collective excitations in the 2DES is discussed.     

Choice of the substrate material for deposition of a superconducting coating

The corrosion resistance of a series of materials (ceramic, beryllium, carbopyroceram) in a niobiumcontaining melt of the composition NaCl–KCl–NaF (10 wt %)–K₂NbF₇ (8 wt %) was studied. The electrolysis parameters ensuring the deposition of uniform 40–50-µm-thick niobium coatings on spherical carbopyroceram substrates were determined.     

Catalytic coatings of new generation based on Mo2C and a microstructured reactor for steam conversion of carbon monoxide

Cathodic processes occurring in the course of molybdenum hemicarbide synthesis on molybdenum supports (Mo₂C/Mo) were studied by cyclic voltammetry. The coatings synthesized were tested as catalysts in steam conversion of carbon monoxide. The catalytic activity of the Mo₂C/Mo system in this reaction is higher by 1–3 orders of magnitude than that of the commercial catalyst Cu/ZnO/Al₂O₃. A microstructured heat-exchanging reactor was designed and fabricated on the basis of the kinetic data obtained.     

Pi-donor BETS based bifunctional superconductor with polymeric dicyanamidomanganate(II) anion layer: kappa-(BETS)2Mn[N(CN)2]3

Crystals of the bis(ethylenedithio)tetraselenafulvalene (BETS) radical cation salt with dicyanamidomanganate(II) anion, kappa-(BETS)2Mn[N(CN)2]3, were synthesized, which combine conducting and magnetic properties at ambient pressure and are superconducting (Tc approximately/= 5 K) at a moderate pressure of 0.3 kbar.     

Anodic synthesis and properties of polyaminothiazole

The possibility of electrooxidative polymerization of 2-aminothiazole in aqueous and organic media is studied using the cyclic voltammetry method. Anodic synthesis conditions are found that provide the polyaminothiazole conducting film synthesis on platinum and tin dioxide electrodes. IR and electron spectroscopy studies show that the polymer synthesized on the electrode surface contains fragments of π-conjugated bonds that provide optical absorption in the visible region and electrochemical activity of the film. A scheme is suggested for the reactions of oxidative coupling of 2-aminothiazole.