The narrow underdoped-overdoped regime of hole-doped cuprate
superconductors between optimal (p_opt = 0.16) and critical doping (p_c =
0.2) is associated with the closure of the large pseudogap, exhibits striking
discontinuities on both, high and low energy scales. Prominent are the
maxima of the condensation energy and the critical current, the collapse of
the bulge in the basal plane area and of the columnar nanosized patterns of
4a charge density modulations, the martensitic displacements of the planar
oxygens, the steep increase of the carrier density from n=p to n=1+p. We
model these observations with an hole-electron liquid in a
doped antiferromagnetic substrate, governed by the formation of spatially
extended holes encapsulating local p-d hybridization. Their correlations are
not replica of the quasiparticle interactions and Bogoliubov modes are
remnant in the normal pseudogap regime. This mixed conductivity is
discussed in terns of H. Welker's [1] Ansatz symmetrizing asymmetrically
overlapping electron/hole bands in respect to the area with infinite
effective mass ("Freiheitszahl" f=0).
[1] H. Welker, Z. Naturforsch, 3a, 461 (1948); S.-B. math.-naturwiss. Abt.
Bayer. Akad. Wiss. 39 (1981)