Spectral signatures of magnetic Bloch oscillations in one-dimensional easy-axis ferromagnets

TL;DR

This paper studies magnetic Bloch oscillations in one-dimensional easy-axis ferromagnets, providing analytical spectra and structure factors, and predicts spectral signatures relevant for specific materials.

Contribution

It introduces an analytical approach based on noninteracting domain-wall bound states to describe Bloch oscillations in ferromagnets, improving upon previous single domain-wall models.

Findings

Identification of the Wannier-Zeeman ladder in the spectrum.

Analytical expressions for the dynamic structure factor.

Predictions for experimental signatures in CoCl2·2H2O.

Abstract

Domain walls in a one-dimensional gapped easy-axis ferromagnet can exhibit Bloch oscillations in an applied magnetic field. We investigate how exchange couplings modify this behavior within an approximation based on noninteracting domain-wall bound states. In particular, we obtain analytical results for the spectrum and the dynamic structure factor, and show where in momentum space to expect equidistant energy levels, the Wannier-Zeeman ladder, which is the spectral signature of magnetic Bloch oscillations. We compare our results to previous calculations employing a single domain-wall approximation, and make predictions relevant for the material $CoCl2\cdot2H2O$.