Spin Dynamics for the t-J Model

TL;DR

This paper investigates the finite-temperature spin dynamics of the t-J model using fermion-spin theory, revealing frequency-separated spectra and temperature-dependent low-frequency behavior consistent with experiments and simulations.

Contribution

It introduces a detailed analysis of spin dynamics in the t-J model at finite temperature, highlighting the separation of spectral components and their temperature dependence.

Findings

High- and low-frequency parts of the spin spectrum are separated.

High-frequency part is suppressed in the dynamical susceptibility.

Low-frequency part varies with temperature, matching experimental observations.

Abstract

The spin dynamics at the finite temperature for the t-J model in the underdoped and optimal doped regimes is studied within the fermion-spin theory. It is shown that the dynamical spin structure factor spectrum at the antiferromagnetic wave vector $Q=(\pi,\pi)$ are separated as low- and high-frequency parts, respectively, but the high-frequency part is suppressed in the dynamical susceptibility spectrum $\chi^{''}(Q,\omega)$, while the low-frequency part is the temperature dependent, which are in qualitative agreement with the experiments and numerical simulations.