Current Status of Fermi Liquid Based Approaches to the Cuprates

Abstract

A central issue in the field of high temperature superconductivity is the nature of the normal state. Here we review normal state transport, thermodynamic, magnetic and spectroscopic data and discuss their interpretation within a Fermi liquid based framework. It is demonstrated that the cuprate data are not consistent with canonical Fermi liquid behavior. However, if the Fermi liquid is characterized by low energy scales, arising from narrow bandwidths or soft spin fluctuations, then canonical behavior is not expected at the relatively “high” temperatures of the normal state. We discuss two main Fermi liquid based schools, i.e., the “almost localized” and “almost magnetic” descriptions. Both approaches have addressed the data with some success and it is clear that they are, in many respects, closely related. Here it is claimed that the strongest support for a Fermi liquid based approach to the cuprates derives from the comparison with other strongly correlated Fermi liquid systems, which exhibit similar normal state anomalies.