论文标题
voi $ _2 $单层中的铁电和铁磁性：dzyaloshinskii-moriya互动的角色
Ferroelectricity and ferromagnetism in VOI$_2$ monolayer: the role of Dzyaloshinskii-Moriya interaction
论文作者
论文摘要
具有内在铁磁性和铁电的多种表面是高度期望但相当罕见的，而大多数铁电磁铁都是抗铁磁磁性的。最近的理论工作[物理学。 Rev. b {\ bf 99}，195434（2019）]预测，氧气vo $ x_2 $（$ x $：halogen）单层是通过违反经验$ d^0 $规则来违反经验$ d^0 $规则的二维多型。最有趣的是，预计会员VOI $ _2 $可以表现出自发的铁磁和铁电性。在这项工作中，我们通过使用密度功能理论和蒙特卡洛模拟来扩展先前关于VOI $ _2 $单层的结构和磁性的研究。具有强旋轨耦合的重元素碘的存在导致极性结构中有效的dzyaloshinskii-moriya相互作用，它有利于短期螺旋螺旋结构。另一个有趣的结果是，现场库仑相互作用可以很大程度上抑制极性扭曲，从而导致属于属性属性的金属元素。因此，VOI2单层是具有螺旋磁化的铁电绝缘子，或者是铁磁金属，而不是铁磁铁电离系统。我们的研究强调了Dzyaloshinskii-Moriya相互作用的关键身体作用。
Multiferroics with intrinsic ferromagnetism and ferroelectricity are highly desired but rather rare, while most ferroelectric magnets are antiferromagnetic. A recent theoretical work [Phys. Rev. B {\bf 99}, 195434 (2019)] predicted that oxyhalides VO$X_2$ ($X$: halogen) monolayers are two-dimensional multiferroics by violating the empirical $d^0$ rule. Most interestingly, the member VOI$_2$ are predicted to exhibit spontaneous ferromagnetism and ferroelectricity. In this work, we extend the previous study on the structure and magnetism of VOI$_2$ monolayer by using density functional theory and Monte Carlo simulation. The presence of the heavy element iodine with a strong spin-orbit coupling leads an effective Dzyaloshinskii-Moriya interaction in the polar structure, which favors a short-period spiral a magnetic structure.. Another interesting result is that the on-site Coulomb interaction can strongly suppress the polar distortion thus leading to a ferromagnetic metallic state. Therefore, the VOI2 monolayer is either a ferroelectric insulator with spiral magnetism or a ferromagnetic metal, instead of a ferromagnetic ferroelectric system. Our study highlights the key physical role of the Dzyaloshinskii-Moriya interaction.
