Triple-meron crystal in high-spin Kitaev magnets

Abstract

Spin textures with nontrivial topology hold great promise in future spintronics applications since they are robust against local deformations. The meron, as one of such spin textures, is widely believed to appear in pairs due to its topological equivalence to a half skyrmion. Motivated by recent progresses in high-spin Kitaev magnets, here we investigate numerically a classical Kitaev-Γ model with a single-ion anisotropy. An exotic spin texture including three merons is discovered. Such a state features a peculiar property with an odd number of merons in one magnetic unit cell and it can induce the topological Hall effect. Therefore, these merons cannot be dissociated from skyrmions as reported in the literature and a general mechanism for such a deconfinement phenomenon calls for further studies. Our work demonstrates that high-spin Kitaev magnets can host robust unconventional spin textures and thus they offer a versatile platform not only for exploring exotic states in spintronics but also for understanding the deconfinement mechanism in the condensed-matter physics and the field theory.

Skyrmion crystals in centrosymmetric triangular magnets under hexagonal and trigonal single-ion anisotropy

“…In addition, the present results give a possibility of realizing further exotic multiple-Q states other than the SkXs, such as the hedgehog lattices [52,53,54,55,56,114,57,115,58,116,59], meron-antimeron crystal [117,60,118,26,61,119], vortex crystal [120,112,121,122,76,123,108,124,109], and bubble state [125,126,127,68,110,111]. Indeed, we found instabilities to-ward the vortex and bubble crystals in the presence of different types of singleion anisotropy, as shown in Figs.…”

Skyrmion crystal with integer and fractional skyrmion numbers in a nonsymmorphic lattice structure with the screw axis

“…In addition, the present results provide a potential realization of multiple-Q spin crystals other than the SkX, such as the meron-antimeron [41,[121][122][123][124][125], hedgehog [126][127][128][129][130][131][132][133][134], vortex [114,115,[135][136][137][138][139][140][141], and bubble crystals [62,[142][143][144][145][146], in nonsymmorphic systems with a screw axis. As these spin textures are stabilized by the anisotropic exchange interaction and the multiple-spin interaction, which have not been taken into account in the present model, further exotic spin textures that have never been reported in the single-layer system might be expected in nonsymmorphic systems with layer degrees of freedom.…”

Skyrmion crystal with integer and fractional skyrmion numbers in a nonsymmorphic lattice structure with the screw axis

“…In addition, the present results provide a potential realization of the multiple-Q spin crystals other than the SkX, such as the meron-antimeron [41,[119][120][121][122][123], hedgehog [124][125][126][127][128][129][130][131][132], vortex [112,113,[133][134][135][136][137][138][139], and bubble crystals [61,[140][141][142][143][144], in the nonsymmorphic systems with the screw axis. As these spin textures are stabilized by the anisotropic exchange interaction and the multiple-spin interaction that have not been taken into account in the present model, further exotic spin textures that have never been reported in the single-layer with the layer degrees of freedom.…”