Low-Frequency Microwave Response of a Quantum Point Contact

JETP Letters - The low-frequency microwave photoconductance of a short (100 nm) quantum point contact based on a high-mobility two-dimensional electron gas in the frequency range of 2–3 GHz...     

Microwave-Induced Magneto-Intersubband Scattering in a Square Lattice of Antidots

JETP Letters - The effect of microwave radiation on low-temperature electron magnetotransport in a square antidot lattice with a period of d ≈ 0.8 µm based on a GaAs quantum well with...     

Modulation of Magneto-Intersubband Oscillations in a One-Dimensional Lateral Superlattice

JETP Letters - Low-temperature magnetotransport in a quasi-two-dimensional electron system based on a selectively doped GaAs quantum well with two occupied quantum-confinement subbands with...     

Microwave response of a ballistic quantum dot

The microwave response (photovoltage and photoconductance) of a lateral ballistic quantum dot made of a high-mobility two-dimensional electron gas in an AlGaAs/GaAs heterojunction has been studied experimentally in the frequency range of 110–170 GHz. It has been found that the asymmetry of the photovoltage with respect to the sign of the magnetic field has mesoscopic character and depends on both the magnetic field and the microwave power. This indicates the violation of the Onsager reciprocity relations regarding the electron-electron interactions in the mesoscopic photovoltaic effect. A strong increase in the conductance of the quantum dot induced by the microwave radiation and unrelated to heating, as well as the microwave-induced magneto-oscillations, has been discovered.     

Zero differential resistance of a two-dimensional electron gas in a one-dimensional periodic potential at high filling factors

The nonlinear magnetotransport of a two-dimensional (2D) electron gas in one-dimensional lateral superlattices based on a selectively doped GaAs/AlAs heterostructure is studied. The one-dimensional potential modulation of the 2D electron gas is performed by means of a series of metallic strips formed on the surface of a heterostructure with the use of electron beam lithography and a lift-off process. The dependence of the differential resistance r_xx on the magnetic field B < 1.5T in superlattices with the period a = 400 nm at a temperature of T = 4.2 K is investigated. It is found that electronic states with r_xx ≈ 0 appear in one-dimensional lateral superlattices in crossed electric and magnetic fields. It is shown that states with r_xx ≈ 0 in 2D electronic systems with one-dimensional periodic modulation arise at the minima of commensurability oscillations of the magnetoresistance.     

Synthesis and thermodynamics of lead(II), manganese(II), and cobalt(II) pivalate complexes

Manganese and cobalt oxopivalates and lead pivalate have been synthesized, mass spectral and thermogravimetric analysis have been performed. Sublimation enthalpies of cobalt and manganese oxopivalates have been determined for the first time, while the sublimation enthalpy of lead pivalate has been found to agree well with literature data. Low sublimation enthalpy, high volatility, and monomolecular composition of gas phase allow one to use these complexes as precursors for preparing oxide films and materials by MOCVD method.     

Thermodynamics and vapor formation features of zinc(II) and tin(II) pivalates

Vapor formation of tin(II) and zinc(II) pivalates were studied using the Knudsen effusion method and mass spectrometry analysis of the gas phase. Sublimation of the tin complex is shown to be accompanied by polymerization of the condensed phase, changing its thermodynamic parameters. The vapor formation of zinc pivalate in the presence of trace amounts of water is accompanied by partial hydrolysis of the condensed phase and sublimation of the sample in the form of Zn₄O(piv)₆ and Zn₂piv₄. The absolute partial pressures and heats of sublimation of the components of the gas phase above tin and zinc complexes are calculated.     

In Situ Reflection Electron Microscopy for the Analysis of Silicon Surface Processes: Sublimation,Electromigration, and Adsorption of Impurity Atoms

Crystallography Reports - The results of recent studies of the structural morphological transformations of Si(111) and Si(100) surfaces using in situ ultrahigh-vacuum reflection electron microscopy...     

Drift of adatoms on the (111) silicon surface under electromigration conditions

The existence of the drift of adatoms on the surface that is induced by an electric current heating a sample under the conditions of sublimation, homoepitaxial growth, and quasiequilibrium on the (111) silicon surface at temperatures above 1050°C has been shown by in situ ultrahigh-vacuum reflection electron microscopy and ex situ atomic-force microscopy. It has been found that the direction of the drift of adatoms is independent of the supersaturation value on the surface. Under these conditions, the drift of adatoms occurs towards underlying terraces, i.e., at 1050–1240°C at the resistive heating of the sample by step-up direct electric current and at 1250–1350°C by step-down current. The presence of the drift of adatoms indicates that adatoms have an effective charge whose value at 1280°C is estimated as 0.07 ± 0.01 of the elementary charge.