Alexander M. Finkel'stein

Weak Localization and Coulomb Interaction in Disordered Systems

Interacting electrons, diffusing in a two-dimensional (2d) disordered system, are studied. The renormalization group equations, including both localization effects and Coulomb correlations, are derived. We encounter a qualitatively new situation: the constants describing electron interaction diverge as a result of the renormalization when a certain scale is achieved, whereas the resistence proves to be finite. Calculation of the spin density correlation function reveals that the system exhibits a tendency for spin density rearrangement.

Spin Polarization of Electrons by Nonmagnetic Heterostructures: The Basics of Spin Optics

We propose to use the lateral interface between two regions with different strengths of the spin-orbit interaction(s) to spin polarize the electrons in gated two-dimensional semiconductor heterostructures. For a beam with a nonzero angle of incidence, the transmitted electrons will split into two spin polarization components propagating at different angles. We analyze the refraction at such an interface and outline the basic schemes for filtration and control of the electron spin.

Metal-Insulator Transition in Disordered Two-Dimensional Electron Systems

We present a theory of the metal-insulator transition in a disordered two-dimensional electron gas. A quantum critical point, separating the metallic phase, which is stabilized by electronic interactions, from the insulating phase, where disorder prevails over the electronic interactions, has been identified. The existence of the quantum critical point leads to a divergence in the density of states of the underlying collective modes at the transition, causing the thermodynamic properties to behave critically as the transition is approached. We show that the interplay of electron-electron interactions and disorder can explain the observed transport properties and the anomalous enhancement of the spin susceptibility near the metal-insulator transition.

Suppression of superconductivity in homogeneously disordered systems

Abstract The mean-field theory of the superconductivity transition in homogeneously disordered films together with related experiments are reviewed.

Dilute electron gas near the metal-insulator transition: Role of valleys in silicon inversion layers

Dilute electron gas near the metal-insulator transition in two dimensions.

Effects of Zn substitution for Cu atoms in lanthanum-strontium superconductors

Abstract Electron paramagnetic resonance (EPR) investigations of the La 1− x Sr x Cu 1− y Zn y O 4 compound have been undertaken in order to determine the nature of high- T c superconductivity suppression by doping with nonmagnetic ions. The appearance of a new resonance line with Zn doping was observed. Analysis of this signal reveals that Zn substitution induces the creation of localized magnetic moments, which are localized on Cu ions. The string mechanism of this phenomenon, based on the local U(1) gauge symmetry of the electron spin liquid, is outlined. According to this mechanism, near each substituted ion a spinon-holon pair forms, which reveals the properties of the localized magnetic moments. The peculiarities of superconductivity suppression in the presence of these Zn-stimulated complexed are discussed. The experimental results can be used for the verification of various microscopic mechanisms of hihg- T c superconductivity.

SUPPRESSION OF TC IN SUPERCONDUCTING AMORPHOUS WIRES

The suppression of the mean field temperature of the superconducting transition,

Coherent vs. incoherent pairing in 2D systems near magnetic instability

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dc transport in quantum wires

, in homogeneous amorphous wires is studied. We develop a theory that gives

First Order Superconducting Transition Near a Ferromagnetic Quantum Critical Point

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