Theoretical Prediction of Antiferromagnetic Skyrmion Crystal in Janus Monolayer CrSi₂N₂As₂

Abstract

An antiferromagnetic skyrmion crystal (AF-SkX), a regular array of antiferromagnetic skyrmions, is a fundamental phenomenon in the field of condensed-matter physics. So far, very few proposals have been made to realize the AF-SkX, and most have been based on three-dimensional (3D) materials. Herein, using first-principles calculations and Monte Carlo simulations, we report the identification of AF-SkX in a twodimensional lattice of the Janus monolayer CrSi 2 N 2 As 2 . Arising from the broken inversion symmetry and strong spin−orbit coupling, a large Dzyaloshinskii−Moriya interaction is obtained in the Janus monolayer CrSi 2 N 2 As 2 . This, combined with the geometric frustration of its triangular lattice, gives rise to the skyrmion physics and long-sought AF-SkX in the presence of an external magnetic field. More intriguingly, this system presents two different antiferromagnetic skyrmion phases, and such a phenomenon is distinct from those reported in 3D systems. Furthermore, by contacting with Sc 2 CO 2 , the creation and annihilation of AF-SkX in Janus monolayer CrSi 2 N 2 As 2 can be achieved through ferroelectricity. These findings greatly enrich the research on antiferromagnetic skyrmions.

A strain induced polar metal phase in a ferromagnetic Fe3GeTe2 monolayer

“…A ‘magnetic polar metal’ which integrates magnetism, electric polarization, and metallicity may have potential applications in the field of information storage, 1 multiferroics, 2,3 spintronics, 4 magnetic skyrmions, 5–7 spin Hall effects, 8 etc. Unfortunately, few such systems are known as electric polarization usually counteracts ferromagnetism and conductivity.…”

d0 Magnetic Skyrmions in Two‐Dimensional Lattice

“…[14][15][16][17] Recently, with the discovery of ferromagnetism in Cr 2 Ge 2 Te 6 , [18] CrI 3 [19] and VSe 2 , [20] 2D magnetic crystals are at the frontier of material research, and intensive efforts are devoted to exploit magnetic skyrmions in 2D lattices. [21][22][23][24][25][26][27][28][29] DOI: 10.1002/adfm.202301817 Despite the huge interest, the current magnetic skyrmion research exclusively focuses on d-orbital magnetism. [21][22][23][24][25][26][27][28][29] Physically, arising from the particular orbital nature, d-orbital magnetism typically exhibits a large magnetic moment.…”

“…[21][22][23][24][25][26][27][28][29] DOI: 10.1002/adfm.202301817 Despite the huge interest, the current magnetic skyrmion research exclusively focuses on d-orbital magnetism. [21][22][23][24][25][26][27][28][29] Physically, arising from the particular orbital nature, d-orbital magnetism typically exhibits a large magnetic moment. This makes the magnetic properties, including topological spin textures, sensitive to the external magnetic field B.…”

“…This makes the magnetic properties, including topological spin textures, sensitive to the external magnetic field B. [14][15][16][17]2126] Besides the magnetic field, d-orbital magnetism has another inherent disadvantage in achieving ideal magnetic skyrmions, that is, all magnetic moments are strongly localized, which tends to render weak exchange interaction, leading to the possibly resultant topological spin textures vulnerable to temperature T. [24][25][26][27]30] Because of these facts, the magnetic skyrmions reported in all previous works (either traditional bulk and thin film systems [6,31,32] or 2D crystals [25,26,33] ) can only exist in an extremely narrow window of T-B phase diagram. This rises an outstanding challenge for the field of magnetic skyrmions.…”

Ultrasmall Polar Skyrmions and Merons in SrTiO3 Heterostructures by Polaron Engineering

“…Topological objects with skyrmionic textures have attracted considerable attention due to their exotic phenomenon and enablement of potential applications, such as racetrack memories. − Investigation of skyrmions has been widely conducted in magnetic systems because the formation of skyrmions mainly relies on the existence of intrinsic chiral interactions among spins, i.e., Dzyaloshinskii-Moriya (DM) interactions. − In contrast to the case of magnetic systems, polar skyrmions had long been out of reach in the exploitation of topological objects in ferroelectrics due to the absence of such chiral interactions. Recently, a plethora of nontrivial polar topological structures, including flux-closure domain, vortex, and skyrmions, have been gradually explored in different ferroelectric systems with confined geometries, such as nanocomposites and superlattices.…”