Dynamical properties of S=1 bond-alternating Heisenberg chains at finite temperatures

TL;DR

This paper investigates the finite-temperature dynamical properties of S=1 bond-alternating Heisenberg chains, revealing how temperature affects magnon peaks and excitation spectra using an effective-field approximation.

Contribution

It introduces a finite-temperature analysis of dynamical structure factors in S=1 bond-alternating chains using the pair dynamical correlated-effective-field approximation.

Findings

Sharp one-magnon peak broadens with temperature

Additional weak peak appears at higher energy with increasing temperature

Results are consistent with exact diagonalization methods

Abstract

Dynamical structure factors of the S=1 bond-alternating spin chains in the dimer phase are calculated at finite temperature, using the pair dynamical correlated-effective-field approximation. At T=0, the delta-function-type peak of the one-magnon mode appears. When temperature is increased, such a sharp peak is broadened and the additional weak peak caused by the excitation from the triplet state to the quintet state emerges in the higher energy region. The results are discussed in comparison with those obtained by the exact diagonalization method.