http://dspace.nbuv.gov.ua:80/handle/123456789/115068 2026-04-24T00:48:09Z 2026-04-24T00:48:09Z Monarkha, Yu.P. http://dspace.nbuv.gov.ua:80/handle/123456789/118442 2017-05-31T00:02:39Z 2011-01-01T00:00:00Z

Microwave-induced magnetooscillations and absolute negative conductivity in the multisubband twodimensional electron system on liquid helium Monarkha, Yu.P. It is shown that a nonequilibrium filling of an upper surface subband induced by the microwave resonance can be the origin of the absolute negative conductivity and zero-resistance states for the two-dimensional electron system on liquid helium under magnetic field applied normally. Contrary to the similar effect reported for semiconductor systems, an oscillating sign-changing correction to the dc-magnetoconductivity appears due to quasi-elastic inter-subband scattering which does not involve photons. The analysis given explains remarkable magnetooscillations and zero-resistance states recently observed for electrons on liquid helium.

2011-01-01T00:00:00Z Khotkevych, N.V. Kolesnichenko, Yu.A. van Ruitenbeek, J.M. http://dspace.nbuv.gov.ua:80/handle/123456789/118441 2017-05-31T00:02:35Z 2011-01-01T00:00:00Z

Quantum interference effects in a system of two tunnel point-contacts in the presence of single scatterer: simulation of a double-tip STM experiment Khotkevych, N.V.; Kolesnichenko, Yu.A.; van Ruitenbeek, J.M. The conductance of systems containing two tunnel point-contacts and a single subsurface scatterer is investigated theoretically. The problem is solved in the approximation of s-wave scattering giving analytical expressions for the wave functions and for the conductance of the system. Conductance oscillations resulting from the interference of electron waves passing through different contacts and their interference with the waves scattered by the defect are analyzed. The prospect for determining the depth of the impurity below the metal surface by using the dependence of the conductance as a function of the distance between the contacts is discussed. It is shown that the application of an external magnetic field results in Aharonov–Bohm type oscillations in the conductance, the period of which allows detection of the depth of the defect in a double tip STM experiment.

2011-01-01T00:00:00Z Kirichenko, O.V. Peschansky, V.G. http://dspace.nbuv.gov.ua:80/handle/123456789/118440 2017-05-31T00:02:34Z 2011-01-01T00:00:00Z

Diamagnetism of layered organic conductors Kirichenko, O.V.; Peschansky, V.G. Temperature dependence of the magnetic susceptibility of layered organic conductors with an arbitrary dispersion law, placed in a strong magnetic field, is analyzed. It is shown that quasi-two-dimensional character of the electron energy spectrum of such conductors results in strong dependence of the diamagnetic contribution to the magnetization upon the applied magnetic field orientation. Experimental investigation of the anisotropy of the magnetic susceptibility makes it possible to study separately the diamagnetic and paramagnetic contributions to the magnetization of layered conductors.

2011-01-01T00:00:00Z Fedorchenko, A.V. Grechnev, G.E. Desnenko, V.A. Panfilov, A.S. Gnatchenko, S.L. Tsurkan, V.V. Deisenhofer, J. Krug von Nidda, H.-A. Loidl, A. Chareev, D.A. Volkova, O.S. Vasiliev, A.N. http://dspace.nbuv.gov.ua:80/handle/123456789/118439 2017-05-31T00:02:38Z 2011-01-01T00:00:00Z

Magnetic and superconducting properties of FeSe₁–xTex (x≃0, 0.5, and 1.0) Fedorchenko, A.V.; Grechnev, G.E.; Desnenko, V.A.; Panfilov, A.S.; Gnatchenko, S.L.; Tsurkan, V.V.; Deisenhofer, J.; Krug von Nidda, H.-A.; Loidl, A.; Chareev, D.A.; Volkova, O.S.; Vasiliev, A.N. Magnetization studies for FeSe₁–xTex (x≃0, 0.5, and 1.0) compounds were carried out in magnetic fields up to 50 kOe and in the temperature range 2–300 K. The superconducting transition was observed at Tc≃8 K and 13.6–14.2 K in FeSe₀.₉₆₃ and FeSe₀.₅Te₀.₅, respectively. For the most samples, a nonlinear behavior of the magnetization curves in the normal state gives evidence of a commonly observed substantial presence of ferromagnetic impurities in the compounds under study. By taking these impurity effects into account, the intrinsic magnetic susceptibility χ of FeSe₀.₉₆₃ and FeSe₀.₅Te₀.₅, and FeTe was estimated to increase gradually with Te content. For FeTe a drastic drop in χ(T) with decreasing temperature was found at TN≃70 K, which is presumably related to antiferromagnetic ordering. To shed light on the observed magnetic properties, ab initio calculations of the exchange enhanced magnetic susceptibility are performed for FeSe and FeTe within the local spin density approximation.

2011-01-01T00:00:00Z