共查询到20条相似文献,搜索用时 0 毫秒
1.
A. Komnik R. Egger 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,19(2):271-280
We study nonlinear transport for two coupled one-dimensional quantum wires or carbon nanotubes described by Luttinger liquid
theory. Transport properties are shown to crucially depend on the contact length L
c. For a special interaction strength, the problem can be solved analytically for arbitrary L
c. For point-like contacts and strong interactions, a qualitatively different picture compared to a Fermi liquid emerges, characterized
by zero-bias anomalies and strong dependence on the applied cross voltage. In addition, pronounced Coulomb drag phenomena
are important for extended contacts.
Received 28 July 2000 相似文献
2.
V.I. Fernández A. Iucci C.M. Naón 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,30(1):53-56
We present an extension of the Tomonaga-Luttinger model in which left and right-moving particles have different Fermi velocities.
We derive expressions for one-particle Green's functions, momentum-distributions, density of states, charge compressibility
and conductivity as functions of both the velocity difference ε and the strength of the interaction β. This allows us to identify
a novel restricted region in the parameter space in which the system keeps the main features of a Luttinger liquid but with
an unusual behavior of the density of states and the static charge compressibility κ. In particular κ diverges on the boundary
of the restricted region, indicating the occurrence of a phase transition.
Received 20 May 2002 / Received in final form 23 August 2002 Published online 19 November 2002 相似文献
3.
P. Auban-Senzier C. Lenoir P. Batail D. Jérome S. Tomić 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,7(4):529-532
An investigation of the different contributions leading to charge localization in a 1/2 or 1/4 filled band 1D conductor has
been conducted through a study of transport properties in the solid solution [(TMTSF)1-x (TMTTF) x]2ReO4. The existence of an ordering transition of the anions allows to identify two contributions to the electronic potential with
wave vector 4kF. A dominant on-site 4kF potential besides the bond contribution is revealed when Umklapp scattering is pertinent via the weakening of the localization arising at the (0, 1/2, 1/2) anion ordering which is stabilized under pressure in the compound
[(TMTSF) 0.5 (TMTTF)0.5]2ReO4
at variance with the enhancement of localization observed in the homomolecular (TMTTF)2ReO 4 material.
Received: 13 May 1998 / Revised: 8 July 1998 / Accepted: 9 July 1998 相似文献
4.
M. Brunner F.F. Assaad A. Muramatsu 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,16(2):209-212
We present a new finite-temperature quantum Monte Carlo algorithm to compute imaginary-time Green functions for a single hole
in the t-J model on non-frustrated lattices. Spectral functions are obtained with the Maximum Entropy method. Simulations of the one-dimensional
case show that a simple charge-spin separation Ansatz is able to describe the overall features of the spectral function such as the bandwidth and the compact support of the spectral function, over the whole energy range for values of J
/
t from 1/3 to 4. This is contrasted with the two-dimensional case. The quasiparticle weight Zk is computed on lattices up to L
=128 sites in one dimension, and scales as .
Received 15 February 2000 相似文献
5.
K.-V. Pham M. Gabay P. Lederer 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,9(4):573-576
Standard bosonization techniques lead to phonon-like excitations in a Luttinger liquid (LL), reflecting the absence of Landau
quasiparticles in these systems. Yet in addition to the above excitations some LL are known to possess solitonic states carrying
fractional quantum numbers (e.g. the spin 1/2 Heisenberg chain). We have reconsidered the zero modes in the low-energy spectrum of the Gaussian boson LL Hamiltonian
both for fermionic and bosonic LL: in the spinless case we find that two elementary excitations carrying fractional quantum
numbers allow to generate all the charge and current excited states of the LL. We explicitly compute the wavefunctions of
these two objects and show that one of them can be identified with the 1D version of the Laughlin quasiparticle introduced
in the context of the Fractional Quantum Hall effect. For bosons, the other quasiparticle corresponds to a spinon excitation.
The eigenfunctions of Wen's chiral LL Hamiltonian are also derived: they are quite simply the one dimensional restrictions
of the 2D bulk Laughlin wavefunctions.
Received 26 January 1999 and Received in final form 21 April 1999 相似文献
6.
We consider one-dimensional (1D) interacting spinless fermions with a non-linear spectrum in a clean quantum wire (non-linear
bosonization). We compute diagrammatically the 1D dynamical structure factor, S(ω,q), beyond the Tomonaga approximation focusing
on it's tails, |ω| ≫vq,
i.e. the 2-pair excitation continuum due to forward scattering. Our methodology reveals three classes of diagrams: two “chiral”
classes which bring divergent contributions in the limits ω→±vq, i.e. near the single-pair excitation continuum, and a “mixed”
class (so-called Aslamasov-Larkin or Altshuler-Shklovskii type diagrams) which is crucial for the f-sum rule to be satisfied.
We relate our approach to the T=0 ones present in the literature. We also consider the
case and show that the 2-pair excitation continuum dominates the single-pair one in the range: |q|T/kF ≪ω±vq ≪T (substantial for q ≪kF). As applications we first derive the small-momentum optical conductivity due to forward scattering: σ∼1/ω for T ≪ω and σ∼T/ω2 for T ≫ω. Next, within the 2-pair excitation continuum, we show that the attenuation rate of a coherent mode of dispersion
Ωq crosses over from
, e.g. γq ∼|q|3 for an acoustic mode, to
, independent of Ωq, as temperature increases. Finally, we show that the 2-pair excitation continuum yields subleading curvature corrections
to the electron-electron scattering rate:
, where V is the dimensionless strength of the interaction. 相似文献
7.
V. Meden W. Metzner U. Schollwöck O. Schneider T. Stauber K. Schönhammer 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,16(4):631-646
We present a study of the one-particle spectral properties for a variety of models of Luttinger liquids with open boundaries.
We first consider the Tomonaga-Luttinger model using bosonization. For weak interactions the boundary exponent of the power-law
suppression of the spectral weight close to the chemical potential is dominated by a term linear in the interaction. This
motivates us to study the spectral properties also within the Hartree-Fock approximation. It already gives power-law behavior
and qualitative agreement with the exact spectral function. For the lattice model of spinless fermions and the Hubbard model
we present numerically exact results obtained using the density-matrix renormalization-group algorithm. We show that many
aspects of the behavior of the spectral function close to the boundary can again be understood within the Hartree-Fock approximation.
For the repulsive Hubbard model with interaction U the spectral weight is enhanced in a large energy range around the chemical potential. At smaller energies a power-law suppression,
as predicted by bosonization, sets in. We present an analytical discussion of the crossover and show that for small U it occurs at energies exponentially (in -1/U) close to the chemical potential, i.e. that bosonization only holds on exponentially small energy scales. We show that such a crossover can also be found in other
models.
Received 8 February 2000 and Received in final form 25 April 2000 相似文献
8.
L. Mayrhofer M. Grifoni 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,56(2):107-125
We present a low energy-theory for non-linear transport in finite-size
interacting single-wall carbon nanotubes. It is based on a microscopic
model for the interacting pz electrons and successive bosonization.
We consider weak coupling to the leads and derive equations of motion
for the reduced density matrix. We focus on the case of large-diameter nanotubes where exchange effects can be neglected.
In this situation the energy spectrum is highly degenerate. Due to the multiple degeneracy, diagonal as well as off-diagonal
(coherences)
elements of the density matrix contribute to the nonlinear transport.
At low bias, a four-electron periodicity with a characteristic ratio
between adjacent peaks is predicted. Our results are in quantitative
agreement with recent experiments. 相似文献
9.
P. Pirooznia P. Kopietz 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,58(3):291-296
We calculate the damping γq of collective density oscillations
(zero sound) in a
one-dimensional Fermi gas
with dimensionless forward scattering interaction
F and quadratic energy dispersion
k2 / 2 m at zero temperature.
Using standard many-body perturbation theory,
we obtain γq from the expansion
of the
inverse irreducible polarization to first order
in the effective screened (RPA) interaction.
For wave-vectors | q| /kF ≪F (where kF = m vF is the Fermi wave-vector)
we find to leading order γq ∝| q |3 /(vF m2).
On the other hand, for F ≪| q| /kF most of the spectral weight
is carried by the particle-hole continuum, which is
distributed over a frequency interval of the order of q2/m.
We also show that zero sound damping
leads to a finite maximum proportional to
|k - kF | -2 + 2 η
of the charge peak in the single-particle
spectral function, where η is the anomalous
dimension. Our prediction agrees with photoemission data for
the blue bronze K0.3MoO3.
We comment on other recent calculations of γq. 相似文献
10.
Gun Sang Jeon Chia-Chen Chang Jainendra K. Jain 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,55(3):271-282
We review and extend the composite fermion theory for semiconductor quantum dots in high magnetic fields. The mean-field model
of composite fermions is unsatisfactory for the qualitative physics at high angular momenta.
Extensive numerical calculations demonstrate that the microscopic CF theory,
which incorporates interactions between composite fermions, provides an excellent qualitative and quantitative account
of the quantum dot ground state down to the largest angular momenta studied,
and allows systematic improvements by inclusion of mixing between composite
fermion Landau levels (called Λ levels). 相似文献
11.
P. Fertey M. Poirier P. Batail 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,10(2):305-309
We report a microwave study of the longitudinal and transverse transport properties of the quasi-one-dimensional organic conductor
(TMTSF)2PF6 in its normal phase. The contactless technique have provided a direct measurement of the temperature profile of the resistivity
along the b' direction and in magnetic fields up to 14 T. A characteristic energy scale ( K) has been observed which delimits a transient regime from an insulating to a metallic behavior. This anomalous profile
is discussed in terms of the onset of coherent transport properties along the b' direction below 40 K. This is also supported by the observation of a finite longitudinal and transverse magnetoresistances
only below 40 K, indicative of a two-dimensional regime. Below Tx, however, strong deviations with respect to a Fermi liquid behavior are evidenced.
Received 27 January 1999 相似文献
12.
13.
H. Nélisse C. Bourbonnais H. Touchette Y.M. Vilk A.-M.S. Tremblay 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,12(3):351-365
The temperature-dependent uniform magnetic susceptibility of interacting electrons in one dimension is calculated using several
methods. At low temperature, the renormalization group reveals that the Luttinger liquid spin susceptibility approaches zero temperature with an infinite slope in striking contrast with the Fermi liquid result and with the behavior
of the compressibility in the absence of umklapp scattering. This effect comes from the leading marginally irrelevant operator,
in analogy with the Heisenberg spin 1/2 antiferromagnetic chain. Comparisons with Monte Carlo simulations at higher temperature
reveal that non-logarithmic terms are important in that regime. These contributions are evaluated from an effective interaction
that includes the same set of diagrams as those that give the leading logarithmic terms in the renormalization group approach.
Comments on the third law of thermodynamics as well as reasons for the failure of approaches that work in higher dimensions
are given.
Received 2 March 1999 相似文献
14.
E. Orignac Y. Suzumura 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,23(1):57-67
We study the interplay of Anderson localization and interaction in a two chain Hubbard ladder allowing for arbitrary ratio
of disorder strength to interchain coupling. We obtain three different types of spin gapped localized phases depending on
the strength of disorder: a pinned 4k
F Charge Density Wave (CDW) for weak disorder, a pinned 2k
F CDWπ for intermediate disorder and two independently pinned single chain 2k
F CDW for strong disorder. Confinement of electrons can be obtained as a result of strong disorder or strong attraction. We
give the full phase diagram as a function of disorder, interaction strength and interchain hopping. We also study the influence
of interchain hopping on localization length and show that localization is enhanced by a small interchain hopping but suppressed
by a large interchain hopping.
Received 6 April 2001 相似文献
15.
J.E. Espinosa O. Navarro M. Avignon 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,18(1):9-16
A real-space method has been introduced to study the pairing problem within the generalized Hubbard Hamiltonian. This method
includes the bond-charge interaction term as an extension of the previously proposed mapping method [1] for the Hubbard model.
The generalization of the method is based on mapping the correlated many-body problem onto an equivalent site- and bond-impurity
tight-binding one in a higher dimensional space, where the problem can be solved exactly. In a one-dimensional lattice, we
analyzed the three particle correlation by calculating the binding energy at the ground state, using different values of the
bond-charge, the on-site (U) and the nearest-neighbor (V) interactions. A pairing asymmetry is found between electrons and holes for the generalized hopping amplitude, where the
hole pairing is not always easier than the electron case. For some special values of the hopping parameters and for all kinds
of interactions in the Hubbard Hamiltonian, an analytical solution is obtained.
Received 21 January 2000 and Received in final form 18 July 2000 相似文献
16.
A scattering approach for correlated one-dimensional systems is developed. The perfect contact to charge reservoirs is encoded
in time-dependent boundary conditions. The conductance matrix for an arbitrary gated wire, respecting charge conservation,
is expressed through a dynamic scattering matrix. Two applications are developed. First, it is shown that the dc conductance
is equal to e
2/h for any model with conserved total left- and right-moving charges. Second, the ac conductance matrix is explicitly computated
for the Tomonaga-Luttinger model (TLL).
Received 31 August 1998 相似文献
17.
J. Dietel T. Koschny W. Apel W. Weller 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,5(3):439-445
We reconsider the theory of the half-filled lowest Landau level using the Chern-Simons formulation and study the grand-canonical
potential in the random-phase approximation (RPA). Calculating the unperturbed response functions for current- and charge-density
exactly, without any expansion with respect to frequency or wave vector, we find that the integral for the ground-state energy
converges rapidly (algebraically) at large wave vectors k, but exhibits a logarithmic divergence at small k. This divergence originates in the k-2 singularity of the Chern-Simons interaction and it is already present in lowest-order perturbation theory. A similar divergence
appears in the chemical potential. Beyond the RPA, we identify diagrams for the grand-canonical potential (ladder-type, maximally
crossed, or a combination of both) which diverge with powers of the logarithm. We expand our result for the RPA ground-state
energy in the strength of the Coulomb interaction. The linear term is finite and its value compares well with numerical simulations
of interacting electrons in the lowest Landau level.
Received: 19 February 1998 / Revised: 25 March 1998 / Accepted: 17 April 1998 相似文献
18.
O. Ciftja 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,13(4):671-677
The experimentally observed filling factors of the fractional quantum Hall effect can be described in terms of the composite
fermion wave function of the Jastrow-Slater form [0pt] fully projected into the lowest Landau level. The Slater determinant of the above composite fermion wave function represents
the filled Landau levels of composite fermions evaluated at the corresponding reduced magnetic field. For a system of fermions
studied in the thermodynamic limit, we prove that in the even-denominator-filled state limit (when the number of filled Landau
levels of composite fermions becomes infinite), the above composite fermion wave function exactly transforms into the Rezayi-Read
Fermi-sea-like wave function [0pt] constructed by attaching 2m flux quanta to the Slater determinant of two-dimensional free fermions at the density corresponding to that filling. We study
the composite fermion wave function and its evolution into the Fermi-sea-like wave function for a range of filling factors
very close to the even-denominator-filled state.
Received 19 March 1999 相似文献
19.
Received: 3 April 1998 相似文献
20.
W. Henderson V. Vescoli P. Tran L. Degiorgi G. Grüner 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,11(3):365-368
Optical experiments are reported for the metallic state of the linear chain compound (TMTSF)2ClO4. For the electric field polarized both along the highly (a) and intermediately (b
) conducting directions, a zero energy (ZE) mode and a finite energy mode (FE) are observed. The large anisotropy in the spectral
weight of the FE mode is consistent with the band structure, however the spectral weight of the ZE mode is surprisingly isotropic.
In the least conducting (c
*) direction, the low frequency optical conductivity along with the dc conductivity indicate the presence of a (small) Drude
component only at temperatures below 10 K. These observations provide evidence for a correlation induced semimetallic state,
with a 3D to 2D crossover with increasing temperature.
Received 20 May 1999 相似文献