Mass-energy equivalence for terahertz magnon excitation in antiferromagnetic domain walls

TL;DR

This paper demonstrates the mass-energy equivalence in antiferromagnetic domain walls by showing that magnon excitation results from DW mass loss, enabling relativistic physics studies and efficient THz magnon generation.

Contribution

It introduces a numerical investigation of mass-energy equivalence in AFM domain walls, linking magnon excitation to DW mass loss and broadening, beyond Lorentz contraction effects.

Findings

Magnon energy originates from DW mass loss.

DW width broadening accompanies magnon excitation.

Results enable relativistic physics studies in AFM textures.

Abstract

The theory of special relativity is one of the most significant achievements in modern physics, with several important predictions such as time dilation, size contraction for a moving object and mass-energy equivalence. Recent studies have demonstrated size contraction for an antiferromagnetic (AFM) domain wall (DW). Here, we show the mass-energy equivalence by numerically investigating the excitation of terahertz (THz) magnons from a moving AFM DW under the magnetic anisotropy energy gradient. The energy of magnons comes from the loss of DW mass, accompanied with a DW width broadening, overcoming the Lorentz contraction effect. Our results pave the way to study relativistic physics in AFM textures and to efficiently generate THz magnons by electric means.