Schematic phase diagrams of the cuprates: generally accepted version (a) and a “discussable” one (b). The antiferromagnetic phase (AF), superconducting phase (SC), spin glass (SG) as well as a crossover, , to a pseudogap region are well established,1,2 while a number of other regions are a matter of scientific discussion.3 Here, together with the lines that confine a region of fluctuations either of superconducting4 or “competing order”5 (e.g., AF, charge density waves, or spin-charge ordering), we plot a crossover either between marginal Fermi-liquid (MFL) and usual FL or between incoherent and coherent states of a “slave” boson (see Ref. 6 and references therein). Different regions at lower doping are proposed for different stripe phases7 which can result in the insulating (Ins) and spin-glass regions.3,7
Electronic structure in the antinodal region (along XMY cut). Bare band structure (a) and ARPES snapshots taken at (below ) for an overdoped sample (OD, , ) (b) and underdoped sample (UD, ) (d), and for UD77 at (c). On panels (b) and (c) two split bands are well visible, while on panel (d) a strong depletion of the spectrum can be seen at some “mode” energy.12
Fermi surfaces measured on pristine Bi-2212 (a) and on superstructure-free lead-doped Bi(Pb)-2212 (b).34
The bare band dispersion, as extracted from experiment:20 (a) Fermi surfaces, the dotted square denotes the boundary of the 1st BZ, the triangle shows the path along which the dispersion is shown on panel (b); (c) the corresponding density of states (DOS) with two van Hove singularities close to .
Nodal spectra analysis.16 (a) Bare band dispersion (solid line) and renormalized dispersion (points) on top of the spectral weight of interacting electrons (in gray scale). Though intended to be general, this sketch represents the nodal direction of an underdoped Bi-2212. The illustrations for the Auger-like scattering (b) and scattering by bosons (c). The real (d) and imaginary (e) parts of the self-energy for different doping levels. The solid line in (e) represents a Fermi liquid parabola—the Auger-like scattering.
The best known representatives for the nodal and antinodal regions: (a) a “ kink” on the renormalized dispersion16 and (b) a “peak-dip-hump” (PDH) line shape of a EDC.12
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