2023 journal article
Electrical control of antiferromagnetic domain walls in Weyl semimetals
PHYSICAL REVIEW B, 107(9).
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(OpenAlex)
Source: Web Of Science
Added: May 1, 2023
The electric-field-induced angular force on the N\'eel vector in antiferromagnetic (AFM) Weyl semimetals (WSMs) is theoretically investigated. Unlike in the ferromagnetic (FM) counterparts, the magnetic textures in the AFM WSMs, such as the domain walls (DWs) appear to lack the torsion in the magnetization and, thus, unable to benefit from this highly efficient mechanism that originates from the axial magnetic effect. Contrarily, our calculations illustrate that the addition of the Dzyaloshinskii-Morya interaction can introduce a twist in the magnetization around the DW location, giving rise to a nonzero axial magnetic field. This axial magnetic field, when combined with an external electric field, can lead to an imbalance in the fermion density of Weyl cones of opposite chirality and, thus, a spatially localized net electron spin polarization. The resulting effective exchange field can exert an angular force on the AFM textures for spatial movement, which can be significant in certain AFM WSMs even under a moderate external electric field. The dynamics of the DW motion under this emergent angular force is analyzed by considering the balance of energy absorption and dissipation. Our investigation reveals the need to account for the contribution of the exchange dissipation mechanism beyond the typical Gilbert-like (relativistic) term to compensate the unusual superlinear rate of energy absorption by the AFM textures. The obtained DW velocity vs electric-field characteristics show a significant speedup for the N\'eel DWs in the AFM WSMs over the counterparts in the FM WSMs as well as those in the nontopological magnets. The analysis also elucidates the dependence of the DW motion on the DW chirality in these materials. Our results clearly indicate the significance of the energy-efficient axial magnetic effect in the dynamics of spin textures in AFM WSMs with broken inversion symmetry.