Dichotomy in the T -linear resistivity in hole-doped cuprates

Abstract

From analysis of the in-plane resistivity ρ ab ( T ) of La 2− x Sr x CuO 4 , we show that normal state transport in overdoped cuprates can be delineated into two regimes in which the electrical resistivity varies approximately linearly with temperature. In the low-temperature limit, the T -linear resistivity extends over a very wide doping range, in marked contrast to expectations from conventional quantum critical scenarios. The coefficient of this T -linear resistivity scales with the superconducting transition temperature T c , implying that the interaction causing this anomalous scattering is also associated with the superconducting pairing mechanism. At high temperatures, the coefficient of the T -linear resistivity is essentially doping independent beyond a critical doping p crit =0.19 at which the ratio of the two coefficients is maximal. Taking our cue from earlier thermodynamic and photoemission measurements, we conclude that the opening of the normal-state pseudogap at p crit is driven by the loss of coherence of anti-nodal quasi-particles at low temperatures.