Gurzhi, Kopeliovich, Kalinenko, Yanovskiy Research Group
Research Group: 1-st row on photo (from left) : Alexander Kopeliovich, Radii Gurzhi , 2-nd row: Alexander Kalinenko and Andrey Yanovskiy
Research interests: theory of electron and spin transport in three- and two-dimensional conducting systems
1. A theory of kinetic phenomena in two-dimensional degenerated electron gas in heterostructures was built. It was shown that electron-electron scattering in such systems acted in a completely different way as compared to the three-dimensional metals. New kinetic effects were predicted, viz. (i) one-dimensional diffusion of charge carriers as a mechanism of charge transport in two-dimensional systems; (ii) the ultra-sensitivity to weak magnetic field of relaxation mechanisms, related to the two-dimensional electron-electron scattering at low temperatures, was predicted. Recently, both these effects and the typical hydrodynamic minimum of the electric resistance of two-dimensional high-mobility GaAs/AlGaAS channels have been observed experimentally by the group of Prof. L. W.Molenkamp (Würzburg, Germany).
2. A theory of propagation of electron beams in a two-dimensional degenerated electron gas was built. The theory was used to propose and develop a scattering spectroscopy method made it possible to find experimentally the specific two-dimensional features of the electron-electron scattering predicted by the group members earlier. The nonlinear effect of the heating of electron beams in a two dimensional electron gas was predicted and observed experimentally later.
3. A ‘‘spin-guide’’ source was proposed. This device makes possible a long-distance transmission of currents with a high degree of spin polarization. Under certain conditions a spin-guide could generate an almost ideally spin-polarized current, even when the magnetic material used is not fully polarized. The detailed theory of the spin-guide structures was developed and a number of schemes of spin field-effect transistor both with electrical and magnetic control were proposed and investigated theoretically. The role of electron-electron collisions in the charge and momentum transport in hybrid magnetic/nonmagnetic structures was discussed.
4. A theory of the injection of super narrow beams into solid state structures through the micro- and nano-constrictions of arbitrary shape was developed.
A number of effects which were predicted by the group members have been found experimentally in the research laboratories in Russia, Europe and the USA. Now the group is engaged in the following joint projects: (i) researches in the field of spin transport theory in collaboration with the group of Prof. Uzi Landman (Georgia Institute of Technology, Atlanta, USA); (ii) kinetic phenomena in a two-dimensional electron gas in heterostructures in collaboration with the experimental group of Prof. Laurens Molenkamp (Würzburg University, Würzburg, Germany).
5. A scheme of a transistor device which may amplifie and generate an a.c. spin signal has been proposed. This device exploits the spatial separation of the spin components of the current and the electric gates in a special hybrid magnetic-nonmagnetic structure. The construction of such a device should be feasible with current materials and fabrication techniques.
List of selected publications:
R.N. Gurzhi, A.N .Kalinenko, A.I. Kopeliovich, Electron-Electron Collisions and a New Hydrodynamic Effect in Two-Dimensional Electron Gas, Phys. Rev. Lett., 72, 3872 (1995).
R.N. Gurzhi, A.N. Kalinenko, A.I. Kopeliovich, Electron-Electron Momentum Relaxation in a Two-Dimensional Electron Gas, Phys. Rev. B 52, 4744 (1995).
R.N. Gurzhi, A.N. Kalinenko, A.I. Kopeliovich, The Theory of Kinetic Effects in Two-Dimensional Degenerate Gas of Colliding eletrons, Fiz. Nizk. Temp., 23, 58 ( 1997) ) [Low Temp. Phys., 23, 44, (1997)].
H. Buhmann, R.N. Gurzhi, A.N. Kalinenko, A.I. Kopeliovich, L.V. Molenkamp, A.V. Yanovsky, H. Predel, Effects of Electron-Electron Scattering on Electron-Beam Propagation in a Two-Dimensional Electron-Gas, Phys. Rev. B 62, 2057 (2000).
A.V. Yanovsky, H. Predel., H. Buhmann, R.N. Gurzhi, A.N. Kalinenko, A.I. Kopeliovich, L.W. Molenkamp, Angle-Resolved Spectroscopy of Electron-Electron Scattering in a 2d System, Europhys. Lett., 56, 709 (2001).
R. N. Gurzhi, A. M. Kalinenko, A. I. Kopeliovich, and A. V. Yanovsky, Nonmagnetic Spin-Guides and Spin Transport in Semiconductors, Fiz. Nizk. Temp., 24, 120 (2001).
R.N. Gurzhi, A.N. Kalinenko, A.I. Kopeliovich, A.V. Yanovsky, E.N. Bogachek, and Uzi Landman, Influence of Electron-Electron Scattering on Spin-Polarized Current States in Magnetic Wrapped Nanowires, Fiz. Nizk. Temp., 29, 809 (2003) [Low Temp. Phys. 29, 606 (2003)].
R.N. Gurzhi, A.N. Kalinenko, A.I. Kopeliovich, A.V. Yanovsky, E.N. Bogachek, and Uzi Landman, Spin-Guide Source of High Spin-Polarized Current, Phys. Rev. B 68, 125113 (2003).
R.N. Gurzhi, A.I. Kopeliovich, A.N. Kalinenko, A.V. Yanovsky, E.N. Bogachek, and Uzi Landman. H. Buhmann, L.W. Molenkamp, Relaxation of High-Energy Quasiparticle Distributions: Electron-Electron Scattering in a Two-Dimensional Electron Gas, Phys. Rev. B 68, 165318 (2003).
R.N. Gurzhi, A.N. Kalinenko, A.I. Kopeliovich, A.V. Yanovsky, E.N. Bogachek, and Uzi Landman, A Magnetic-Field Effect Transistor and Spin Transport, Apl. Phys. Lett. 83, 4577 (2003).