Evolution of the low energy spin dynamics in electron-doped high-transition temperature superconductor Pr0.88LaCe0.12CuO4-d

摘要

We use inelastic neutron scattering to explore the evolution of the lowenergy spin dynamics in the electron-doped cuprate Pr0.88LaCe0.12CuO4-d (PLCCO)as the system is tuned from its nonsuperconducting, as-grown antiferromagnetic(AF) state into an optimally-doped superconductor (Tc~24 K) without static AForder. The low temperature, low energy response of the spin excitations inunder-doped samples is coupled to the presence of the AF phase, whereas thelow-energy magnetic response for samples near optimal Tc exhibits spinfluctuations surprisingly insensitive to the sample temperature. This evolutionof the low energy excitations is consistent with the influence of a quantumcritical point in the phase diagram of PLCCO associated with the suppression ofthe static AF order. We carried out scaling analysis of the data and discussthe influence of quantum critical dynamics in the observed excitation spectrum.