15 research outputs found
Universal Behavior and the Two-component Character of Magnetically Underdoped Cuprate Superconductors
We present a detailed review of scaling behavior in the magnetically
underdoped cuprate superconductors (hole dopings less than 0.20) and show that
it reflects the presence of two coupled components throughout this doping
regime: a non-Landau Fermi liquid and a spin liquid whose behavior maps onto
the theoretical Monte Carlo calculations of the 2D Heisenberg model of
localized Cu spins for most of its temperature domain. We use this mapping to
extract the doping dependence of the strength, of the spin liquid
component and the effective interaction, J_eff(x) between the remnant localized
spins that compose it; we find both decrease linearly with x as the doping
level increases. We discuss the physical origin of pseudogap behavior and
conclude that it is consistent with scenarios in which the both the large
energy gaps found in the normal state and their subsequent superconductivity
are brought about by the coupling between the Fermi liquid quasiparticles and
the spin liquid excitations, and that differences in this coupling between the
1-2-3 and 2-1-4 materials can explain the measured differences in their
superconducting transition temperatures and other properties.Comment: 80 pages, 43 figure
Keldysh technique and non-linear sigma-model: basic principles and applications
The purpose of this review is to provide a comprehensive pedagogical
introduction into Keldysh technique for interacting out-of-equilibrium
fermionic and bosonic systems. The emphasis is placed on a functional integral
representation of underlying microscopic models. A large part of the review is
devoted to derivation and applications of the non-linear sigma-model for
disordered metals and superconductors. We discuss such topics as transport
properties, mesoscopic effects, counting statistics, interaction corrections,
kinetic equation, etc. The sections devoted to disordered superconductors
include Usadel equation, fluctuation corrections, time-dependent
Ginzburg-Landau theory, proximity and Josephson effects, etc. (This review is a
substantial extension of arXiv:cond-mat/0412296.)Comment: Review: 103 pages, 19 figure
Charge density waves in solids
The latest addition to this series covers a field which is commonly referred to as charge density wave dynamics.The most thoroughly investigated materials are inorganic linear chain compounds with highly anisotropic electronic properties. The volume opens with an examination of their structural properties and the essential features which allow charge density waves to develop.The behaviour of the charge density waves, where interesting phenomena are observed, is treated both from a theoretical and an experimental standpoint. The role of impurities in statics and dynamics is considered and a