Doping dependence of spin excitations in the stripe phase of high-Tc superconductors

TL;DR

This study uses a Gutzwiller approximation to analyze how spin excitations in stripe phases of high-Tc superconductors depend on doping, providing quantitative predictions aligned with experimental observations.

Contribution

It introduces a detailed theoretical approach to predict doping-dependent spin excitation spectra in stripe phases, improving understanding of magnetic modes in high-Tc cuprates.

Findings

Weak linear doping dependence of resonance energy below 1/8 doping

Resonance energy shifts higher when charge deviates from half-filling

Spin-wave velocity shows a minimum at 1/8 doping, correlating with Tc anomaly

Abstract

Based on the time-dependent Gutzwiller approximation for the extended Hubbard model we calculate the energy and momentum dependence of spin excitations for striped ground states. Our starting point correctly reproduces the observed doping dependence of the incommensurability in La-based cuprates and the dispersion of magnetic modes in the insulating parent compound. This allows us to make quantitative predictions for the doping evolution of the dispersion of magnetic modes in the stripe phase including the energy and intensity of the resonance peak as well as the velocity of the spin-wave like Goldstone mode. In the underdoped regime $n_h<1/8$ we find a weak linear dependence of $\omega_{res}$ on doping whereas the resonance energy significantly shifts to higher values when the charge concentration in the stripes starts to deviate from half-filling for $n_h>1/8$. The velocity $c$ is non-monotonous with a minimum at 1/8 in coincidence with a well known anomaly in $T_c$. Our calculations are in good agreement with available experimental data. We also compare our results with analogous computations based on linear spin-wave theory.