Abstract
Recently, the doping dependence of the optical-conductivity scattering rate has been used by Hwang, Timusk, and Gu to gain some insight in the way the coupling between the charge carriers and the bosonic modes in high- superconductors depends on doping. These authors used the extended Drude analysis, which does not take into account the normal-state pseudogap explicitly. In this work, we calculated the optical conductivity within the rotating antiferromagnetism theory, which models explicitly the pseudogap. Then we analyzed the resistivity as a function of temperature and doping . We extracted the scattering rate by fitting the resistivity data. We found that for smaller than a critical value , shows a marginal-Fermi-liquid dependence for greater than a -dependent temperature . But for deviates downward from this law. We attribute this depression to a stronger coupling between the charge carriers and the normal-state bosonic modes. Both this coupling and vanish at while superconductivity continues to be significant well above it. is interpreted as a quantum critical point, and as the pseudogap temperature because it is found to agree with the experimental data on . We propose that a possible candidate for the bosonic modes may be the spin-wave excitations in the rotating frame of the rotating antiferromagnetic order.
7 More- Received 19 September 2005
DOI:https://doi.org/10.1103/PhysRevB.72.184518
©2005 American Physical Society