Linear resistivities in the copper oxides: Fermi-liquid-based approaches

Mechanisms for a linear temperature-dependent resistivity are discussed in Fermi-liquid-based approaches. For realistic models of the cuprates this behavior arises for temperatures T above the Van Hove energy scale ${\mathit{T}}^{\mathrm{*}}$<50 K. This crossover temperature is substantially reduced in magnitude by Coulomb correlations for a wide range of hole concentrations. Calculations of the spectral function ${\mathrm{\alpha }}^2$F show important q structure and therefore differences with the ‘‘marginal’’ ansatz. Spin-spin interactions adversely affect the linear resistivity when the system is close to an antiferromagnetic instability. Comparison with NMR calculations indicates that different energy scales are playing a role in resistivity and NMR probes, as observed experimentally.