A Theoretical Approach to Pseudogap and Superconducting Transitions in Hole-Doped Cuprates
Figure 4
(a) A plot of the upper and the lower bands in the pure DDW state (doping level 9.94%) along the antinodal cut --. The back-bending (or saturation) momentum of the dispersion and the Fermi momentum are indicated. The numerical values, in the units of the first neighbor hopping , are , the PG gap amplitude , and the SC gap amplitude . The hopping parameters are and . The DDW ordering leads to pining of the Fermi level close to, but not precisely at, the Van Hove singularity. (b) A plot of the upper and the lower bands in the pure SC state along the antinodal cut -- indicating perfect electron-hole symmetry (both the upper and lower bands are parabolic). The numerical value of the SC gap amplitude . The hopping parameters values and are the same as above. (c) A plot of the upper bands and the lower bands in the DDW-DSC state along the antinodal cut --. The back-bending (or saturation) momentum of the dispersion is indicated by double-headed arrows. This shoulder-type feature also exists in the experimental data of Hashimoto et al. [24]. Evidently, there are four quasiparticle bands (shown as a function of momentum along the antinodal cut) with two positioned at negative energy and two at positive energy for the Fermi energy taken as zero. The parameter values used are , the PG gap amplitude , and the SC gap amplitude . The hopping parameters are and .
