Doping Dependence of the Pseudogap in La(2-x)Sr(x)CuO(4)

TL;DR

This study uses Raman scattering to investigate how the pseudogap in La(2-x)Sr(x)CuO(4) varies with doping, revealing its decline with increased hole concentration and suggesting different origins for the pseudogap and superconducting gap.

Contribution

It provides new experimental evidence on the doping dependence of the pseudogap in La(2-x)Sr(x)CuO(4) using Raman scattering, highlighting the anisotropic quasiparticle interactions.

Findings

Pseudogap spectral weight diminishes with doping.

Strong anisotropic quasiparticle interactions are observed.

Pseudogap vanishes at optimal doping.

Abstract

We report the results of Raman scattering experiments on single crystals of La(2-x)Sr(x)CuO(4) that span the range from underdoped (x = 0.10) to overdoped (x =0.22). The spectra are consistent with the existence of a strong anisotropic quasiparticle interaction that results in a normal state depletion of spectral weight from regions of the Fermi surface located near the zone axes. The strength of the interaction decreases rapidly with increasing hole concentration and the spectral evidence for the pseudogap vanishes when the optimum doping level is reached. The results suggest that the pseudogap and superconducting gap arise from different mechanisms.