The emergence of coherent magnetic excitations in the pseudogap phase of La2-xSrxCuO4

TL;DR

This study uses inelastic neutron scattering to reveal the development of coherent magnetic excitations in La2-xSrxCuO4 as it enters the pseudogap phase, showing a transition from damped to structured magnetic behavior.

Contribution

It provides new insights into magnetic excitation behavior in the pseudogap phase of cuprate superconductors using detailed neutron scattering measurements.

Findings

Magnetic excitations become highly structured below 60 meV in the pseudogap phase.

At high temperatures, magnetic excitations are strongly damped with a characteristic energy of ~50 meV.

Development of the pseudogap correlates with changes in magnetic excitation structure.

Abstract

We use inelastic neutron scattering to measure the magnetic excitations in the underdoped superconductor La2-xSrxCuO4 (x=0.085, Tc=22 K) over energy and temperatures ranges 5 < E < 200 meV and 5 < T < 300 K respectively. At high temperature (T = 300 K), we observe strongly damped excitations with a characteristic energy scale of approximately 50 meV. As the temperature is lowered to T = 30 K, and we move into the pseudogap state, the magnetic excitations become highly structured in energy and momentum below about 60 meV. This change appears to be associated with the development of the pseudogap in the electronic excitations.