42 research outputs found
Reply to 'Comment on "Dynamic correlations of the spinless Coulomb Luttinger liquid [Phys. Rev. B 65, 125109 (2002)]"'
We show that the criticism of our paper [Phys. Rev. B 65, 125109 (2002)] by
Wang, Millis, and Das Sarma [cond-mat/0206203] is based on a trivial
mathematical mistake they have committed.Comment: 2 pages, no figure
Electron transport in a quantum wire with realistic Coulomb interaction
Electron transport in a quantum wire with leads is investigated with actual
Coulomb interaction taken into account. The latter includes both the direct
interaction of electrons with each other and their interaction via the image
charges induced in the leads. Exact analytical solution of the problem is found
with the use of the bosonization technique for one-dimensional electrons and
three-dimensional Poisson equation for the electric field. The Coulomb
interaction is shown to change significantly the electron density distribution
along the wire as compared with the Luttinger liquid model with short-range
interactions. In DC and low frequency regimes, the Coulomb interaction causes
the charge density to increase strongly in the vicinity of the contacts with
the leads. The quantum wire impedance shows an oscillating behavior versus the
frequency caused by the resonances of the charge waves. The Coulomb interaction
produces a frequency dependent renormalization of the charge wave velocity.Comment: 10 two-colomn revtex pages, 6 postscript figures; one figure changed,
some typos corrected, to be published in Phys.Rev.
Effect of short-range electron correlations in dynamic transport in a Luttinger liquid
The density operator in the Luttinger model consists of two components, one
of which describes long-wave fluctuations and the other is related to the rapid
oscillations of the charge-density-wave (CDW) type, caused by short-range
electron correlations. It is commonly believed that the conductance is
determined by the long-wave component. The CDW component is considered only
when an impurity is present. We investigate the contribution of this component
to the dynamic density response of a Luttinger liquid free from impurities. We
show that the conventional form of the CDW density operator does not conserve
the number of particles in the system. We propose the corrected CDW density
operator devoid of this shortcoming and calculate the dissipative conductance
in the case when the one-dimensional conductor is locally disturbed by a
conducting probe. The contribution of the CDW component to conductance is found
to dominate over that of the long-wave component in the low-frequency regime.Comment: 6 pages, 4 figures; updated to the published versio
Effect of Interactions on the Admittance of Ballistic Wires
A self-consistent theory of the admittance of a perfect ballistic, locally
charge neutral wire is proposed. Compared to a non-interacting theory,
screening effects drastically change the frequency behavior of the conductance.
In the single-channel case the frequency dependence of the admittance is
monotonic, while for two or more channels collective interchannel excitations
lead to resonant structures in the admittance. The imaginary part of the
admittance is typically positive, but can become negative near resonances.Comment: Presentation considerably modified; the results are unchanged. 4
pages, 2 figures .eps-format include
Deformed Wigner crystal in a one-dimensional quantum dot
The spatial Fourier spectrum of the electron density distribution in a finite
1D system and the distribution function of electrons over single-particle
states are studied in detail to show that there are two universal features in
their behavior, which characterize the electron ordering and the deformation of
Wigner crystal by boundaries. The distribution function has a -like
singularity at the Fermi momentum . The Fourier spectrum of the density
has a step-like form at the wavevector , with the harmonics being absent
or vanishing above this threshold. These features are found by calculations
using exact diagonalization method. They are shown to be caused by Wigner
ordering of electrons, affected by the boundaries. However the common Luttinger
liquid model with open boundaries fails to capture these features, because it
overestimates the deformation of the Wigner crystal. An improvement of the
Luttinger liquid model is proposed which allows one to describe the above
features correctly. It is based on the corrected form of the density operator
conserving the particle number.Comment: 10 pages, 11 figures. Misprints fixe
Mechanism of electron localization in a quantum wire
We show that quasi-bound electron states are formed in a quantum wire as a
result of electron backscattering in the transition regions between the wire
and the electron reservoirs, to which the wire is coupled. The backscattering
mechanism is caused by electron density oscillations arising even in smooth
transitions due to the reflection of electrons not transmitting through the
wire. The quasi-bound states reveal themselves in resonances of the electron
transmission probability through the wire. The calculations were carried out
within the Hartree-Fock approximation using quasiclassic wavefunctions.Comment: 7 pages, IOP style, 4 figures, typos corrected, published versio
Thermal Wave Induced Edge Electrical Field of Pyroelectric: Spatial Pattern Mapping and Effect of Ambient Conditions
We have recently analyzed theoretically the main characteristics of the edge
depolarizing electric field (EDEF), in the vicinity of a non-polar face of a
pyroelectric. In this work we measured and characterized the EDEF, excited by a
harmonical thermal wave. We present here experimental results obtained on a
pyroelectric crystal LiTaO3, confirming our theoretical predictions. We present
the theoretical analysis and description of the thermal wave and the induced
harmonically varying EDEF. The calculations assume an equivalent circuit of a
pyroelectric capacitive current source. The measured magnitude of the EDEF and
its spatial variation agree well with the theoretical model. The effect of the
air pressure at the pyroelectric/air interface, on the EDEF, was determined in
the interval 10^3 - 10^-6 torr. We found that EDEF increases significantly with
decreasing air pressure, presumably due to diminishing of adsorption screening
at the polar faces. Teflon plates, covering the polar faces, prevent
accumulation of screening charged particles, resulting in a drastic increase of
EDEF
Interaction Constants and Dynamic Conductance of a Gated Wire
We show that the interaction constant governing the long-range
electron-electron interaction in a quantum wire coupled to two reservoirs and
capacitively coupled to a gate can be determined by a low frequency
measurement. We present a self-consistent, charge and current conserving theory
of the full conductance matrix. The collective excitation spectrum consists of
plasma modes with a relaxation rate which increases with the interaction
strength and is inversely proportional to the length of the wire. The
interaction parameter is determined by the first two coefficients of the
out-of-phase component of the dynamic conductance measured at the gate.Comment: 4 pages, LaTeX, 2 figure
Capture of carriers to screened charged centres and low temperature shallow impurity electric field break down in semiconductors
Free carrier capture by a screened Coulomb potential in semiconductors are
considered. It is established that with decreasing screening radius the capture
cross section decreases drastically, and it goes to zero when .
On the basis of this result a new mechanism of shallow impurity electric field
break down in semiconductors is suggested.Comment: 8 pages, latex, 1 figure in gif format, to be submitted to "Journal
of Condensed Matter