2,808 research outputs found
Coulomb drag between one-dimensional conductors
We have analyzed Coulomb drag between currents of interacting electrons in
two parallel one-dimensional conductors of finite length attached to
external reservoirs. For strong coupling, the relative fluctuations of electron
density in the conductors acquire energy gap . At energies larger than
, where
is the impurity scattering rate, and for , where is the
fluctuation velocity, the gap leads to an ``ideal'' drag with almost equal
currents in the conductors. At low energies the drag is suppressed by coherent
instanton tunneling, and the zero-temperature transconductance vanishes,
indicating the Fermi liquid behavior.Comment: 5 twocolumn pages in RevTex, added 1 eps-Figure and calculation of
trans-resistanc
Quantum critical behaviour of the plateau-insulator transition in the quantum Hall regime
High-field magnetotransport experiments provide an excellent tool to
investigate the plateau-insulator phase transition in the integral quantum Hall
effect. Here we review recent low-temperature high-field magnetotransport
studies carried out on several InGaAs/InP heterostructures and an InGaAs/GaAs
quantum well. We find that the longitudinal resistivity near the
critical filling factor ~ 0.5 follows the universal scaling law
, where . The critical exponent equals ,
which indicates that the plateau-insulator transition falls in a non-Fermi
liquid universality class.Comment: 8 pages, accepted for publication in Proceedings of the Yamada
Conference LX on Research in High Magnetic Fields (August 16-19, 2006,
Sendai
Ordered magnetic and quadrupolar states under hydrostatic pressure in orthorhombic PrCu2
We report magnetic susceptibility and electrical resistivity measurements on
single-crystalline PrCu2 under hydrostatic pressure, up to 2 GPa, which
pressure range covers the pressure-induced Van Vleck
paramagnet-to-antiferromagnet transition at 1.2 GPa. The measured anisotropy in
the susceptibility shows that in the pressure-induced magnetic state the
ordered 4f-moments lie in the ac-plane. We propose that remarkable pressure
effects on the susceptibility and resistivity are due to changes in the
quadrupolar state of O22 and/or O20 under pressure. We present a simple
analysis in terms of the singlet-singlet model.Comment: 14 pages, 9 figures submitted to Phys. Rev.
Fractional charge in transport through a 1D correlated insulator of finite length
Transport through a one channel wire of length confined between two leads
is examined when the 1D electron system has an energy gap : induced by the interaction in charge mode (: charge velocity in the
wire). In spinless case the transformation of the leads electrons into the
charge density wave solitons of fractional charge entails a non-trivial low
energy crossover from the Fermi liquid behavior below the crossover energy to the insulator one with the
fractional charge in current vs. voltage, conductance vs. temperature, and in
shot noise. Similar behavior is predicted for the Mott insulator of filling
factor .Comment: 5 twocolumn pages in RevTex, no figure
Detecting synchronization of self-sustained oscillators by external driving with varying frequency
We propose a method for detecting the presence of synchronization of
self-sustained oscillator by external driving with linearly varying frequency.
The method is based on a continuous wavelet transform of the signals of
self-sustained oscillator and external force and allows one to distinguish the
case of true synchronization from the case of spurious synchronization caused
by linear mixing of the signals. We apply the method to driven van der Pol
oscillator and to experimental data of human heart rate variability and
respiration.Comment: 9 pages, 7 figure
Threshold features in transport through a 1D constriction
Suppression of electron current through a 1D channel of length
connecting two Fermi liquid reservoirs is studied taking into account the
Umklapp electron-electron interaction induced by a periodic potential. This
interaction causes Hubbard gaps for . In the perturbative
regime where ( charge velocity), and for small deviations
of the electron density from its commensurate values
can diverge with some exponent as voltage or temperature decreases above
, while it goes to zero below . This results
in a nonmonotonous behavior of the conductance.Comment: Final variant published in PRL, 79, 1714; minor correction
Conductance of a Mott Quantum Wire
We consider transport through a one-dimensional conductor subject to an
external periodic potential and connected to non-interacting leads (a "Mott
quantum wire"). For the case of a strong periodic potential, the conductance is
shown to jump from zero, for the chemical potential lying within the
Mott-Hubbard gap, to the non-interacting value of 2e^2/h, as soon as the
chemical potential crosses the gap edge. This behavior is strikingly different
from that of an optical conductivity, which varies continuously with the
carrier concentration. For the case of a weak potential, the perturbative
correction to the conductance due to Umklapp scattering is absent away from
half-filling.Comment: 4 pages, RevTex, 1 ps figure included; published versio
Scaling of the quantum-Hall plateau-plateau transition in graphene
The temperature dependence of the magneto-conductivity in graphene shows that
the widths of the longitudinal conductivity peaks, for the N=1 Landau level of
electrons and holes, display a power-law behavior following with a scaling exponent . Similarly the
maximum derivative of the quantum Hall plateau transitions
scales as with a scaling exponent
for both the first and second electron and hole Landau
level. These results confirm the universality of a critical scaling exponent.
In the zeroth Landau level, however, the width and derivative are essentially
temperature independent, which we explain by a temperature independent
intrinsic length that obscures the expected universal scaling behavior of the
zeroth Landau level
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