Magnetic Excitations of the Diagonal Incommensurate Phase in Lightly-Doped La2-xSrxCuO4

TL;DR

This study investigates magnetic excitations in lightly-doped La2-xSrxCuO4, revealing that the excitation spectrum in the insulating phase with diagonal incommensurate spin modulation closely resembles that in the superconducting phase, with doping-dependent energy crossing points.

Contribution

It demonstrates that the magnetic excitation spectrum in the insulating diagonal incommensurate phase is similar to the superconducting phase, highlighting doping and temperature independence of low-energy dispersion slope.

Findings

Magnetic excitation spectrum is similar in insulating and superconducting phases.

Dispersion slope at low energy is doping and temperature independent.

Energy crossing the antiferromagnetic wave vector increases linearly with doping.

Abstract

We present inelastic neutron scattering experiments on a single-domain crystal of lightly-doped La1.96Sr0.04CuO4. We find that the magnetic excitation spectrum in this insulating phase with a diagonal incommensurate spin modulation is remarkably similar to that in the superconducting regime, where the spin modulation is bond parallel. In particular, we find that the dispersion slope at low energy is essentially independent of doping and temperature over a significant range. The energy at which the excitations cross the commensurate antiferromagnetic wave vector increases roughly linearly with doping through the underdoped regime.