478 research outputs found
How universal is the one-particle Green's function of a Luttinger liquid?
The one-particle Green's function of the Tomonaga-Luttinger model for
one-dimensional interacting Fermions is discussed. Far away from the origin of
the plane of space-time coordinates the function falls off like a power law.
The exponent depends on the direction within the plane. For a certain form of
the interaction potential or within an approximated cut-off procedure the
different exponents only depend on the strength of the interaction at zero
momentum and can be expressed in terms of the Luttinger liquid parameters
and of the model at hand. For a more general
interaction and directions which are determined by the charge velocity
and spin velocity the exponents also depend on the
smoothness of the interaction at zero momentum and the asymptotic behavior of
the Green's function is not given by the Luttinger liquid parameters alone.
This shows that the physics of large space-time distances in Luttinger liquids
is less universal than is widely believed.Comment: 5 pages with 2 figure
Interpretation of Photoemission Spectra of (TaSe4)2I as Evidence of Charge Density Wave Fluctuations
The competition between different and unusual effects in
quasi-one-dimensional conductors makes the direct interpretation of
experimental measurements of these materials both difficult and interesting. We
consider evidence for the existence of large charge-density-wave fluctuations
in the conducting phase of the Peierls insulator (TaSe4)2I, by comparing the
predictions of a simple Lee, Rice and Anderson theory for such a system with
recent angle-resolved photoemission spectra. The agreement obtained suggests
that many of the unusual features of these spectra may be explained in this
way. This view of the system is contrasted with the behaviour expected of a
Luttinger liquid.Comment: Archive copy of published paper. 19 pages, 12 figures, uses IOP
macro
Non-fermi-liquid single particle lineshape of the quasi-one-dimensional non-CDW metal Li_{0.9}Mo_{6}O_{17} : comparison to the Luttinger liquid
We report the detailed non-Fermi liquid (NFL) lineshape of the dispersing
excitation which defines the Fermi surface (FS) for quasi-one-dimensional
Li_{0.9}Mo_{6}O_{17}. The properties of Li_{0.9}Mo_{6}O_{17} strongly suggest
that the NFL behavior has a purely electronic origin. Relative to the
theoretical Luttinger liquid lineshape, we identify significant similarities,
but also important differences.Comment: 5 pages, 3 eps figure
Spectral function of the 1D Hubbard model in the limit
We show that the one-particle spectral functions of the one-dimensional
Hubbard model diverge at the Fermi energy like
in the limit. The Luttinger liquid behaviour
, where as ,
should be limited to (for large but
finite), which shrinks to a single point, ,in that limit.
The consequences for the observation of the Luttinger liquid behaviour in
photoemission and inverse photoemission experiments are discussed.Comment: 4 pages, RevTeX, 2 figures on reques
Crossover from Luttinger- to Fermi-liquid behavior in strongly anisotropic systems in large dimensions
We consider the low-energy region of an array of Luttinger liquids coupled by
a weak interchain hopping. The leading logarithmic divergences can be re-summed
to all orders within a self-consistent perturbative expansion in the hopping,
in the large-dimension limit. The anomalous exponent scales to zero below the
one-particle crossover temperature. As a consequence, coherent quasiparticles
with finite weight appear along the whole Fermi surface. Extending the
expansion self-consistently to all orders turns out to be crucial in order to
restore the correct Fermi-liquid behavior.Comment: Shortened version to appear in Physical Review Letter
Phase diagram of the one-dimensional extended Hubbard model with attractive and/or repulsive interactions at quarter filling
We study the phase diagram of the one dimensional (1D) model at quarter
filling in the most general case where the on-site and first-neighbour
interactions and can be both attractive and repulsive. The results have
been obtained using exact diagonalization of small clusters and variational
techniques, as well as exact results in various limits. We have analyzed four
properties of the groundstate: i)~whether it is insulating or metallic;
\hbox{ii)~whether} it is homogenous or phase separated; iii)~whether it has a
spin gap; iv)~whether it has dominant superconducting fluctuations. With eight
phases, the resulting phase diagram is unexpectedly rich. The four phases not
found in the weak coupling limit are: i) an insulating phase when and
are large enough; ii) a region of phase separation when is attractive; iii)
another region of phase separation when is large enough and small; iv)
a region with dominant superconducting fluctuations when is intermediate
and small. The actual nature of this last phase, which has pairs but no
spin gap, is not fully clear yet.Comment: 24 pages, RevTeX (4 postscript figures attached to the end
Many-body Effects in Angle-resolved Photoemission: Quasiparticle Energy and Lifetime of a Mo(110) Surface State
In a high-resolution photoemission study of a Mo(110) surface state various
contributions to the measured width and energy of the quasiparticle peak are
investigated. Electron-phonon coupling, electron-electron interactions and
scattering from defects are all identified mechanisms responsible for the
finite lifetime of a valence photo-hole. The electron-phonon induced mass
enhancement and rapid change of the photo-hole lifetime near the Fermi level
are observed for the first time.Comment: RevTEX, 4 pages, 4 figures, to be published in PR
Hall effect and conduction anisotropy in the organic conductor TMTSF2PF6
Long missing basic experiments in the normal phase of the anisotropic
electron system of TMTSF2PF6 were performed. Both the Hall effect and the
ab'-plane conduction anisotropy are directly addressing the unconventional
electrical properties of this Bechgaard salt. We found that the dramatic
reduction of the carrier density deduced from recent optical data is not
reflected in an enhanced Hall-resistance. The pressure- and temperature
dependence of the b'-direction resitivity reveal isotropic relaxation time and
do not require explanations beyond the Fermi liquid theory. Our results allow a
coherent-diffusive transition in the interchain carrier propagation, however
the possible crossover to Luttinger liquid behavior is placed to an energy
scale above room temperature.Comment: 5 pages, 5 figures, to be published in Phys. Rev. Let
Generalized Spectral Signatures of Electron Fractionalization in Quasi-One and -Two Dimensional Molybdenum Bronzes and Superconducting Cuprates
We establish the quasi-one-dimensional Li purple bronze as a photoemission
paradigm of Luttinger liquid behavior. We also show that generalized signatures
of electron fractionalization are present in the angle resolved photoemission
spectra for quasi-two-dimensional purple bronzes and certain cuprates. An
important component of our analysis for the quasi-two-dimensional systems is
the proposal of a ``melted holon'' scenario for the k-independent background
that accompanies but does not interact with the peaks that disperse to define
the Fermi surface.Comment: 7 pages, 8 figure
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