10,214 research outputs found
Novel Phenomena in Dilute Electron Systems in Two Dimensions
We review recent experiments that provide evidence for a transition to a
conducting phase in two dimensions at very low electron densities. The nature
of this phase is not understood, and is currently the focus of intense
theoretical and experimental attention.Comment: To appear as a Perspective in the Proceedings of the National Academy
of Sciences. Reference to Chakravarty, Kivelson, Nayak, and Voelker's paper
added (Phil. Mag., in press
Metal-insulator transition in two-dimensional electron systems
The interplay between strong Coulomb interactions and randomness has been a
long-standing problem in condensed matter physics. According to the scaling
theory of localization, in two-dimensional systems of noninteracting or weakly
interacting electrons, the ever-present randomness causes the resistance to
rise as the temperature is decreased, leading to an insulating ground state.
However, new evidence has emerged within the past decade indicating a
transition from insulating to metallic phase in two-dimensional systems of
strongly interacting electrons. We review earlier experiments that demonstrate
the unexpected presence of a metallic phase in two dimensions, and present an
overview of recent experiments with emphasis on the anomalous magnetic
properties that have been observed in the vicinity of the transition.Comment: As publishe
On a complex differential Riccati equation
We consider a nonlinear partial differential equation for complex-valued
functions which is related to the two-dimensional stationary Schrodinger
equation and enjoys many properties similar to those of the ordinary
differential Riccati equation as, e.g., the famous Euler theorems, the Picard
theorem and others. Besides these generalizations of the classical
"one-dimensional" results we discuss new features of the considered equation
like, e.g., an analogue of the Cauchy integral theorem
Quaternion Analysis for Generalized Electromagnetic Fields of Dyons in Isotropic Medium
Quaternion analysis of time dependent Maxwell's equations in presence of
electric and magnetic charges has been developed and the solutions for the
classical problem of moving charges (electric and magnetic) are obtained in
unique, simple and consistent manner
Formation of three-particle clusters in hetero-junctions and MOSFET structures
A novel interaction mechanism in MOSFET structures and
hetero-junctions between the zone electrons of the two-dimensional (2D) gas and
the charged traps on the insulator side is considered. By applying a canonical
transformation, off-diagonal terms in the Hamiltonian due to the trapped level
subsystem are excluded. This yields an effective three-particle attractive
interaction as well as a pairing interaction inside the 2D electronic band. A
type of Bethe- Goldstone equation for three particles is studied to clarify the
character of the binding and the energy of the three-particle bound states. The
results are used to offer a possible explanation of the Metal-Insulator
transition recently observed in MOSFET and hetero-junctions.Comment: 4 page
Magnetic Field Suppression of the Conducting Phase in Two Dimensions
The anomalous conducting phase that has been shown to exist in zero field in
dilute two-dimensional electron systems in silicon MOSFETs is driven into a
strongly insulating state by a magnetic field of about 20 kOe applied parallel
to the plane. The data suggest that in the limit of T -> 0 the conducting phase
is suppressed by an arbitrarily weak magnetic field. We call attention to
striking similarities to magnetic field-induced superconductor-insulator
transitions
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