Theory of Electron Differentiation, Flat Dispersion and Pseudogap Phenomena
arXiv:cond-mat/0005369 · doi:10.1016/S0022-3697(00)00099-8
Abstract
Aspects of electron critical differentiation are clarified in the proximity of the Mott insulator. The flattening of the quasiparticle dispersion appears around momenta $(Ï,0)$ and $(0,Ï)$ on square lattices and determines the criticality of the metal-insulator transition with the suppressed coherence in that momentum region of quasiparticles. Such coherence suppression at the same time causes an instability to the superconducting state if a proper incoherent process is retained. The d-wave pairing interaction is generated from such retained processes without disturbance from the coherent single-particle excitations. Pseudogap phenomena widely observed in the underdoped cuprates are then naturally understood from the mode-mode coupling of d-wave superconducting(dSC) fluctuations with antiferromagnetic ones. When we assume the existence of a strong d-wave pairing force repulsively competing with antiferromagnetic(AFM) fluctuations under the formation of flat and damped single-particle dispersion, we reproduce basic properties of the pseudogap seen in the magnetic resonance, neutron scattering, angle resolved photoemission and tunneling measurements in the cuprates.
9 pages including 2 figures, to appear in J. Phys. Chem. Solids