Antiskyrmions stabilized at interfaces by anisotropic Dzyaloshinskii-Moriya interactions

Abstract

Chiral magnets are an emerging class of topological matter harboring localized and topologically protected vortex-like magnetic textures called skyrmions, which are currently under intense scrutiny as an entity for information storage and processing. Here, on the level of micromagnetics we rigorously show that chiral magnets can not only host skyrmions but also antiskyrmions as least energy configurations over all non-trivial homotopy classes. We derive practical criteria for their occurrence and coexistence with skyrmions that can be fulfilled by (110)-oriented interfaces depending on the electronic structure. Relating the electronic structure to an atomistic spin-lattice model by means of density functional calculations and minimizing the energy on a mesoscopic scale by applying spin-relaxation methods, we propose a double layer of Fe grown on a W(110) substrate as a practical example. We conjecture that ultra-thin magnetic films grown on semiconductor or heavy metal substrates with C 2v symmetry are prototype classes of materials hosting magnetic antiskyrmions.

B–T phase diagram of Pd/Fe/Ir(111) computed with parallel tempering Monte Carlo

“…The latter is enough to stabilize topologically protected states [12,13]. Then, the stability of skyrmions and antiskyrmions [14,15] is enhanced only by DMI [16,17], which occurs when structural inversion symmetry is broken such as in chiral magnets or at surfaces or interfaces [18][19][20].…”

Anisotropic Dzyaloshinskii-Moriya interaction in ultrathin epitaxial Au/Co/W(110)

“…This DMI could be isotropic and should have a DMI strength in between the values found along the bcc[110] and along the bcc[001] directions in the Au/Co/W(110) system. Another possibility would be to use a system suggested recently in a theoretical paper discussing anisotropic DMI and anti-skyrmions in Fe/W(110) [31].…”

Topological–chiral magnetic interactions driven by emergent orbital magnetism

“…We demonstrate that the interactions of the topological orbital moments with each other and with the spins form a new class of magnetic interactions − topological-chiral interactions − which can dominate over the Dzyaloshinskii-Moriya interaction, thus opening a path for realizing new classes of chiral magnetic materials with three-dimensional magnetization textures such as hopfions. Exotic magnetic textures with particle-like properties [1][2][3][4][5][6] offer great potential for innovative spintronic applications 7 and brain-inspired computing 8,9 . Magnetic skyrmions, twodimensional (2D) localized solitons, are a prominent realization of chiral spin structures, first observed in the material class of non-centrosymmetric B20 bulk compounds 1 .…”