Spin Pseudo Gap in La2-xSrxCuO4 Studied by Neutron Scattering

TL;DR

This study investigates spin excitations in La2-xSrxCuO4 using neutron scattering, revealing a spin pseudo gap above Tc that diminishes with temperature and varies with doping levels.

Contribution

It provides experimental evidence of the spin pseudo gap in La2-xSrxCuO4 across different doping levels and temperatures using inelastic neutron scattering.

Findings

Spin pseudo gap observed above Tc in x=0.18 sample.

Pseudo gap gradually collapses between 80 K and 150 K.

Presence of broad bump near 5 meV indicating pseudo gap in normal state.

Abstract

Spin excitations of La2-xSrxCuO have been studied using inelastic neutron scattering techniques in the energy range of 2 meV =< w =< 12 meV and the temperature range of 8 K =< T =< 150 K. We observed a signature of a spin pseudo gap in the excitation spectrum above Tc for the slightly overdoped sample with x = 0.18. On heating, the spin pseudo gap gradually collapses between T = 80 K and 150 K. For the x = 0.15 and 0.20, although the visibility of gap-like structure at T ~ Tc is lower compared to the x = 0.18 sample, the broad bump of kai"(w) appears at w ~ 5 meV,close to the spin-gap energy at base temperature, suggests the existence of the spin pseudo gap in the normal state.