42 research outputs found

    Reply to 'Comment on "Dynamic correlations of the spinless Coulomb Luttinger liquid [Phys. Rev. B 65, 125109 (2002)]"'

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    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

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    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

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    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

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    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

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    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 δ\delta-like singularity at the Fermi momentum kFk_F. The Fourier spectrum of the density has a step-like form at the wavevector 2kF2k_F, 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

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    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

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    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

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    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

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    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 % r_s=a_B^{*}. 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
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