Dynamical quadrupole structure factor of frustrated ferromagnetic chain

TL;DR

This paper studies the dynamical quadrupole structure factor of a frustrated spin chain using DMRG, revealing gapless excitations and their dispersion changes in a magnetic field, advancing understanding of spin nematic phases.

Contribution

It provides the first detailed DMRG analysis of the dynamical quadrupole structure factor in a frustrated ferromagnetic chain under magnetic field.

Findings

Gapless excitations at q=π in the spin nematic regime.

Quadratic dispersion at saturation magnetization.

Linear dispersion as magnetization decreases.

Abstract

We investigate the dynamical quadrupole structure factor of a spin-1/2 $J_{1}$-$J_{2}$ Heisenberg chain with competing ferromagnetic $J_{1}$ and antiferromagnetic $J_{2}$ in a magnetic field by exploiting density-matrix renormalization group techniques. In a field-induced spin nematic regime, we observe gapless excitations at $q=\pi$ according to quasi-long-range antiferro-quadrupole correlations. The gapless excitation mode has a quadratic form at the saturation, while it changes into a linear dispersion as the magnetization decreases.