论文标题
否则挫败感的非欧克拉纳尔多$ q $旋转纹理：单离子各向异性和债券依赖性各向异性的影响
Noncoplanar multiple-$Q$ spin textures by itinerant frustration: Effects of single-ion anisotropy and bond-dependent anisotropy
论文作者
论文摘要
从理论上讲，我们研究了多个波动波的叠置叠置的多键纹理，这些纹理具有不同的波浪数，用于有效的中心对称巡回磁铁的旋转模型。我们的重点是由旋转式耦合和由自旋轨道耦合引起的磁各向异性引起的生物二级相互作用之间的相互作用。考虑到两种类型的磁各向异性，单离子各向异性和粘结依赖性各向异性，我们在没有外部磁场的情况下阐明了原型三角晶格系统的磁相图。在单离子各向异性的情况下，我们发现了很多多重$ Q $不稳定性，具体取决于各向异性的强度和符号（易于平面或易于轴），包括具有两个拓扑数的天空晶体。在外部磁场中，我们发现一个具有拓扑数的天际晶体由易于平面（易于轴）各向异性下的平面内（平面外）磁场稳定。我们还通过旋转场方向来检查场诱导的Skyrmion晶体的稳定性。作为两种双重动物，我们表明，具有非零手性的三重$ q $状态出现在存在于二次相互作用和易于轴各向异性的情况下。同时，我们发现键依赖性各向异性也稳定了两种类型的天际晶体。我们表明，对于具有一个拓扑数的Skyrmion晶体，Bloch-和Néel-type Skyrmion晶体的选择性根据债券依赖性各向异性的迹象选择性地实现。此外，我们发现了另一个多重$ Q $状态，包括两种类型的梅隆晶体，其中有一个和两个。系统的研究将引用中心对称磁力中的复杂磁纹理。
We theoretically investigate multiple-$Q$ spin textures, which are composed of superpositions of spin density waves with different wave numbers, for an effective spin model of centrosymmetric itinerant magnets. Our focus is on the interplay between biquadratic interactions arising from the spin-charge coupling and magnetic anisotropy caused by the spin-orbit coupling. Taking into account two types of the magnetic anisotropy, single-ion anisotropy and bond-dependent anisotropy, we elucidate magnetic phase diagrams for an archetypal triangular-lattice system in the absence and presence of an external magnetic field. In the case of the single-ion anisotropy, we find a plethora of multiple-$Q$ instabilities depending on the strength and the sign of the anisotropy (easy plane or easy axis), including a skyrmion crystal with topological number of two. In an external magnetic field, we find that a skyrmion crystal with topological number of one is stabilized by the in-plane (out-of-plane) magnetic field under the easy-plane (easy-axis) anisotropy. We also examine the stability of the field-induced skyrmion crystal by rotating the field direction. As a biproduct, we show that a triple-$Q$ state with nonzero chirality appears in the presence of the biquadratic interaction and the easy-axis anisotropy. Meanwhile, we find that the bond-dependent anisotropy also stabilizes both types of skyrmion crystals. We show that, however, for the skyrmion crystal with topological number of one, Bloch- and Néel-type skyrmion crystals are selectively realized depending on the sign of the bond-dependent anisotropy. Moreover, we find yet another multiple-$Q$ states, including two types of meron crystals with the skyrmion numbers of one and two. The systematic investigation will provide a reference to complex magnetic textures in centrosymmetric magnetic metals.
