论文标题
刺猬格子和野外诱发的手性在呼吸 - 呼吸chlore Heisenberg Antiferromagnets
Hedgehog lattice and field-induced chirality in breathing-pyrochlore Heisenberg antiferromagnets
论文作者
论文摘要
We theoretically investigate a $J_1$-$J_3$ classical Heisenberg model on the breathing pyrochlore lattice, where the nearest-neighbor (NN) exchange interactions for small and large tetrahedra, $J_1$ and $J_1'$, take different values due to the breathing bond-alternation and $J_3$ is the third NN antiferromagnetic interaction along the bond direction.通过蒙特卡洛模拟发现，对于大$ j_3 $来说，刺猬晶格，三维定期磁性单极和抗巨键杆的阵列以四倍的形式出现 - $ {\ bf q} $由$ {\ bf $ { q} =（\ pm \ frac {1} {2}，\ pm \ frac {1} {2}，\ pm \ pm \ frac {1} {2}）$，无论是$ j_1 $和/或$ j_1'$的符号，无论是$ j_1 $ $ j_1'$ a $还发现，在一个应用的磁场中，有六个四倍 - $ {\ bf q} $状态，具体取决于$ j_1 $和$ j_1'$的值，其中三个阶段在内，包括野外野外野外野外居住状态的nonzero total chirality total chirality total Chirality $ \ mbox $ \ mbox {\ bold $ $ $ usiped usiped usipationus o usiped usiped usiped usipationus手性起源。在剩下的两个手性阶段中，尽管有$ \ mbox {\ boldmath $χ$χ}^{\ rm t} \ neq 0 $ 0 $，但在存在铁磁$ j_1 $和/或$ j_1'$的情况下才实现的。还讨论了单孔的拓扑对象在$ \ mbox {\ boldmath $χ$}^{\ rm t} $中的作用。
We theoretically investigate a $J_1$-$J_3$ classical Heisenberg model on the breathing pyrochlore lattice, where the nearest-neighbor (NN) exchange interactions for small and large tetrahedra, $J_1$ and $J_1'$, take different values due to the breathing bond-alternation and $J_3$ is the third NN antiferromagnetic interaction along the bond direction. It is found by means of Monte Carlo simulations that for large $J_3$, a hedgehog lattice, a three-dimensional periodic array of magnetic monopoles and antimonopoles, emerges in the form of a quadruple-${\bf Q}$ state characterized by the ordering vector of ${\bf Q}=(\pm\frac{1}{2},\pm\frac{1}{2},\pm\frac{1}{2})$, being irrespective of the signs of $J_1$ and/or $J_1'$ as long as $J_1\neq J_1'$. It is also found that in an applied magnetic field, there appear six quadruple-${\bf Q}$ states depending on the values of $J_1$ and $J_1'$, among which three phases including the in-field hedgehog-lattice state exhibit nonzero total chirality $\mbox{\boldmath $χ$}^{\rm T}$ associated with the anomalous Hall effect of chirality origin. In the remaining two chiral phases, which are realized in the presence of ferromagnetic $J_1$ and/or $J_1'$, the spin structure is not topologically nontrivial, in spite of the fact that $\mbox{\boldmath $χ$}^{\rm T} \neq 0$. The role of the topological objects of the monopoles in $\mbox{\boldmath $χ$}^{\rm T}$ is also discussed.
