9,545 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
Superconductivity in correlated disordered two-dimensional electron gas
We calculate the dynamic effective electron-electron interaction potential
for a low density disordered two-dimensional electron gas. The disordered
response function is used to calculate the effective potential where the
scattering rate is taken from typical mobilities from recent experiments. We
investigate the development of an effective attractive pair potential for both
disordered and disorder free systems with correlations determined from existing
numerical simulation data. The effect of disorder and correlations on the
superconducting critical temperature Tc is discussed.Comment: 4 pages, RevTeX + epsf, 4 figure
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
Comment on "Theory of metal-insulator transitions in gated semiconductors" (B. L. Altshuler and D. L. Maslov, Phys. Rev. Lett. 82, 145 (1999))
In a recent Letter, Altshuler and Maslov propose a model which attributes the
anomalous temperature and field dependence of the resistivity of
two-dimensional electron (or hole) systems to the charging and discharging of
traps in the oxide (spacer), rather than to intrinsic behavior of interacting
particles associated with a conductor-insulator transition in two dimensions.
We argue against this model based on existing experimental evidence.Comment: 1 page; submitted to PR
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