1,795 research outputs found
Theory of Lattice and Electronic Fluctuations in Weakly Localized Spin-Peierls Systems
A theoretical approach to the influence of one-dimensional lattice
fluctuations on electronic properties in weakly localized spin-Peierls systems
is proposed using the renormalization group and the functional integral
techniques. The interplay between the renormalization group flow of correlated
electrons and one-dimensional lattice fluctuations is taken into account by the
one-dimensional functional integral method in the adiabatic limit. Calculations
of spin-Peierls precursor effects on response functions are carried out
explicitely and the prediction for the temperature dependent magnetic
susceptibility and nuclear relaxation is compared with available experimental
data for (TMTTF)PF.Comment: 15 pages, 7 Encapsulated Postscript figure
Interplay between spin-density-wave and superconducting states in quasi-one-dimensional conductors
The interference between spin-density-wave and superconducting instabilities
in quasi-one-dimensional correlated metals is analyzed using the
renormalization group method. At the one-loop level, we show how the
interference leads to a continuous crossover from a spin-density-wave state to
unconventional superconductivity when deviations from perfect nesting of the
Fermi surface exceed a critical value. Singlet pairing between electrons on
neighboring stacks is found to be the most favorable symmetry for
superconductivity. The consequences of non uniform spin-density-wave pairing on
the structure of phase diagram within the crossover region is also discussed.Comment: 10 pages RevTex,4 Figures, submitted to EPJ
Interchain-Frustration-Induced Metallic State in Quasi-One-Dimensional Mott Insulators
The mechanism that drives a metal-insulator transition in an undoped
quasi-one-dimensional Mott insulator is examined in the framework of the
Hubbard model with two different hoppings t_{perp 1} and t_{perp 2} between
nearest-neighbor chains. By applying an N_{perp}-chain renormalization group
method at the two-loop level, we show how a metallic state emerges when both
t_{perp 1} and t_{perp 2} exceed critical values. In the metallic phase, the
quasiparticle weight becomes finite and develops a strong momentum dependence.
We discuss the temperature dependence of the resistivity and the impact of our
theory in the understanding of recent experiments on half-filled molecular
conductors.Comment: 4 pages, 3 figures, published versio
Superconductivity close to the charge-density-wave instability
We use the weak coupling renormalization group method to examine the
interplay between charge-density-wave and s-wave superconducting orders in a
quasi-one-dimensional model of electrons interacting with acoustic phonons. The
relative stability of both types of order is mapped out at arbitrary nesting
deviations and Debye phonon frequency . We singled out a power law
increase of the superconducting from a quantum
critical point of charge-density-wave order triggered by nesting alterations.
The results capture the key features shown by the proximity between the two
types of ordering in the phase diagram of the recently discovered Perylene
based organic superconductor under pressure. The impact of Coulomb interaction
on the relative stability of the competing phases is examined and discussed in
connection with the occurrence of s-wave superconductivity in low dimensional
charge-density-wave materials.Comment: 6 pages, 5 figure
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