Dynamical quadrupole structure factor of frustrated ferromagnetic chain

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 = π 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.

Excitation and transport of bound magnon clusters in frustrated ferromagnetic chain

“…We have previously studied the dynamical spin and quadrupole structure factors [10,11,12] and the spin Drude weight [3] with a particular focus on the quadrupole regime. In this paper, to gain further insight into the relation between the low-energy excitation and the spin transport property, we numerically investigate the multi-magnon excitation energy, the dynamical spin, quadrupole, and octupole structure factors, and the spin current correlation function, in the both quadrupole and octupole regimes.…”

Magnetic excitations and transport properties in frustrated ferromagnetic chain

“…Since the quadrupole and longitudinal spin correlations are both quasi-long-ranged, we refer to this phase as the spin-nematic/spin-density-wave (SN/SDW) phase. Many theoretical efforts have been made to clarify dynamical properties [10,11,12,13,14,15,16,17,18], whereas the relevance of magnetic excitations governed by bound magnons to transport properties has not been understood yet.…”