Spin-charge gauge approach to “pseudogap”: theory versus experiments

Abstract

We propose an explanation of several experimental features related to the “pseudogap” in high T c cuprates in terms of a spin-charge gauge theory. In this approach, based on a formal spin-charge separation applied to the t– J model, the low energy effective action describes gapful spinons (with a theoretically derived doping dependence of the gap m s∼ J( δ|ln δ|) 1/2, where δ is the doping concentration) and holons with “small” Fermi surface ( ϵ F∼ tδ) interacting via a gauge field. The main effect of gauge fluctuations is to introduce a dissipation ∼ T/ χ, where χ is the diamagnetic susceptibility. The competition between the two energy scales, m s and T/ χ, is the root in our approach of many phenomena peculiar to transport properties of the “pseudogap phase”. A good agreement is found between the experimental data and theoretically derived doping and temperature dependence of many physical quantities, such as in-plane and out-of-plane resistivity, in-plane magnetoresistance, far infrared electronic AC conductivity and spin lattice relaxation rate.