Spin-charge gauge approach to pseudogap: theory versus experiments

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) similar to J(delta\ ln delta\)(1/2), where delta is the doping concentration) and holons with "small" Fermi surface (epsilon(F) similar to tdelta) interacting via a gauge field. The main effect of gauge fluctuations is to introduce a dissipation similar to T/chi where chi is the diamagnetic susceptibility. The competition between the two energy scales, in, and T/chi 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. (C) 2004 Elsevier B.V. All rights reserved.