论文标题
二维铁磁半导体VBR3，可调节各向异性
Two-dimensional ferromagnetic semiconductor VBr3 with tunable anisotropy
论文作者
论文摘要
二维（2D）铁磁铁（FMS）由于其在自旋应用中的前景而引起了广泛的关注。在这里，我们使用第一原理计算，晶体场水平分析和蒙特卡洛模拟探索了蜂窝晶格中Vbr $ _ {3} $的散装和单层的电子结构和磁性。我们的结果表明，vbr $ _ {3} $ bulk具有$ e'_ {g} $$^2 $（$ s $ = 1）地面状态，并且具有小轨道矩和弱平面磁动率。这些结果很好地解释了最近的实验。更有趣的是，我们发现在半导体VBR $ _ {3} $单层对基态的抗拉力压力中，将基态调整为$ a_ {1g} $$^1 $$^1 $$ e'_ _ {g} $$^1 $，因此产生了一个大的轨道时刻，并且产生了一个强大的偏外型不同的异位型。然后，显着增强的FM superexchange和单离子各向异性（SIA）将从20 K中筹集$ t _ {\ rm c} $，对于裸露的VBR $ _ {3} $单层至100-115 K，在2.5 $ \％$ -5 $ \％$ \％$ \％$ \％$ \％$ \％。因此，vbr $ _ {3} $将是具有可调各向异性的有前途的2D FM半导体。
Two-dimensional (2D) ferromagnets (FMs) have attracted widespread attention due to their prospects in spintronic applications. Here we explore the electronic structure and magnetic properties of the bulk and monolayer of VBr$_{3}$ in the honeycomb lattice, using first-principles calculations, crystal field level analyses, and Monte Carlo simulations. Our results show that VBr$_{3}$ bulk has the $e'_{g}$$^2$ ($S$=1) ground state and possesses a small orbital moment and weak in-plane magnetic anisotropy. Those results well explain the recent experiments. More interestingly, we find that a tensile strain on the semiconducting VBr$_{3}$ monolayer tunes the ground state into $a_{1g}$$^1$$e'_{g}$$^1$ and thus produces a large orbital moment and a strong out-of-plane anisotropy. Then, the significantly enhanced FM superexchange and single ion anisotropy (SIA) would raise $T_{\rm C}$ from 20 K for the bare VBr$_{3}$ monolayer to 100-115 K under a 2.5$\%$-5$\%$ strain. Therefore, VBr$_{3}$ would be a promising 2D FM semiconductor with a tunable anisotropy.
