MAIN ACHIEVEMENTS 2014
1. Relativistic Plasma Mode Detection in a Two-Dimensional Electron System with Exceeding Speed of Light Conductivity. In a two-dimensional electron system with exceeding speed of light conductivity a novel weakly damped mode of plasma oscillations remaining weakly damped right up to room temperatures was detected. The conditions for its existence are high conductivity and the presence of close metal gate that indicates polariton nature. The mode has abnormal small width of the resonance absorption line. There are perspectives for fabrication of this mode based fast detectors and subterahertz radiation generators.
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2. Coulomb Interaction in the Intersecting Electron Beams. Combination of carrier high quality and low density in modern semi-conductive structures enables to study Coulomb phenomena beyond Landau’s description (in fact, in pure limits). In 2014 ISSP RAS researchers have made significant experimental progress in this direction using measurements of nonequilibrium current fluctuations and local bolometry. A small aperture connecting pure two-dimensional electron reservoirs is sensible to inelastic electron-electron scattering in its vicinity due to the disturbance of detailed balance at current flow. The analogue of drag effect between injected and incident electron beams exists; it leads to contact resistance reduction.
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3. Current-Induced Magnetization Dynamics at the Edge of a Two-Dimensional Electron System with Strong Spin-Orbit Coupling Electron transport is experimentally investigated through the interface between a permalloy ferromagnet and the edge of a two-dimensional electron system with strong Rashba-type spin-orbit coupling. Strongly nonlinear transport is observed around zero bias at milli-Kelvin temperatures. The observed nonlinearity is fully suppressed above some critical values of temperature, magnetic field, and current through the interface. This behavior is interpreted as the result of spin accumulation at the interface and its current-induced absorption as a magnetization torque. (Phys. Rev. B 89, 075312 (2014))
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4. Resistive Switching and Diode Properties of Mesoscopic Niobium-Oxide-Based Structures. The fabrication technology is developed and the effects of resistive switchings in niobium-oxide-based structures are studied in ISSP. I-V characteristics of heterostructures consisting of niobium oxide amorphous films have a weak resistive switching effect. However, annealing shifts niobium oxide to the multiphase nanocrystalline state, and arising spatial inhomogeneity in oxygen vacancies leads to reversible switching from the low-resistive to the high-resistive state and the existence of bistable resistive states. This effect is connected with Schottky barrier modulation on the metal-oxide interface. |
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5. The Novel Method for Production of Silicon-Carbide Ceramics Items The novel method of multifunctional silicone-carbide ceramics production based on silicon melt interaction with carbon situated in a beforehand prepared blank with certain composition and porosity was developed in ISSP RAS. Novel structural ceramics has higher operating temperatures, chemical stability, mechanical, thermo-shock and radiation resistance, wear resistance, reliability, service life and parameters stability. It opens broad prospects for its use in chemical, oil-producing and oil-refining industry, and also its use as the components for gas-turbine engines of new generation. |
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Technologies and Equipment for Sapphire Large-Sized Crystal Growing for Wide-Aperture Optics of Aerospace Application, Transparent Armor, Protective Screens for Mobile Device Displays. The technologies and equipment for growing of single-crystal sapphire in the form of plain windows with characteristic size up to 300 mm by Stepanov’s method for transmitting optics and shielding windows for guiding, tracing and recognizing devices and for transparent armor were developed. Technologies and equipment allow one to considerably improve efficiency and reduce prime cost of similar products. |
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7. 2D-Structures Based on Layered Gallium Chalcogenides The methods for GaS1-xSex (x = 0 – 1) layered single crystal growth by vertical zone melting under inert gas pressure were developed in ISSP. Exfoliation of such materials similarly to a grapheme allowed one to fabricate 2D-structures having the area up to 1500 µm2 Photoluminescence of obtained GaSe films ≫ 40 nm thick in microresonators with distributed Bragg reflectors from SiO2/TiO2 quarter-wavelength pairs was studied. At wavelength of 603.7 nm 60-fold Purcell’s amplification of PL intensity in a resonator at the decrease in its damping time by an order of magnitude was observed experimentally. |