Stripe-like Inhomogeneities, Coherence, and the Physics of the High Tc Cuprates
The carriers in the high-Tc cuprates are found to be polaron-like “stripons” carrying charge and located in stripe-like inhomogeneities, “quasi-electrons” carrying charge and spin, and “svivons” carrying spin and some lattice distortion. The anomalous spectroscopic and transport properties of the cuprates are understood. The stripe-like inhomogeneities result from the Bose condensation of the svivon field, and the speed of their dynamics is determined by the width of the double-svivon neutron-resonance peak. The connection of this peak to the peak-dip-hump gap structure observed below Tc emerges naturally. Pairing results from transitions between pair states of stripons and quasi-electrons through the exchange of svivons. The pairing symmetry is of the d x 2−y2 type; however, sign reversal through the charged stripes results in features not characteristic of this symmetry. The phase diagram is determined by pairing and coherence lines within the regime of a Mott transition. Coherence without pairing results in a Fermi-liquid state, and incoherent pairing results in the pseudogap state where localized electron and electron pair states exist within the Hubbard gap. A metal-insulator-transition quantum critical point occurs between these two states at T = 0 when the superconducting state is suppressed. An intrinsic heterogeneity is expected of superconducting and pseudogap nanoscale regions.