论文标题
单层和几层NII $ _ {2} $竞争多种阶段
Competing multiferroic phases in monolayer and few-layer NiI$_{2}$
论文作者
论文摘要
最近的一个实验报告了基于假定的螺旋磁构型（Spiral-B）的单层（ML）NII $ _ {2} $中的II型多效性，正如我们在这里发现的，在ML限制中，这是我们在此处发现的。独立的ml nii $ _ {2} $打破了其c $ _ {3} $对称性，因为它更喜欢条纹的抗铁磁序（AABB-AFM），以及内部的抗抗抗抗逆抗抗逆抗抗反铁（AFE（AFE）订单。但是，底物限制可以保留C $ _ {3} $对称性和/或将拉伸应变应用于ML。这导致了另一个螺旋磁顺序（螺旋 - $ iv^x $），而2L显示了不同的顺序（螺旋 - $ v^y $），而螺旋-B则以较厚的层为主。因此，三个多性阶段，即螺旋 - b+fe，螺旋 - $ iv^x $+fe，螺旋 - $ v^y $+fe，一个抗多源的aabb-abb-abb-abb-afm+afe，显示了依赖于厚度的thicknickness thicknickness thicknickness依赖于厚度且依赖于厚度的kiitext and tipertent and tipertent and依赖的kitren kitren，依赖于kitrentent and tipertent and依赖于kitrentent的kitren依赖的kitrane，相互作用和单离子磁各向异性。我们的理论结果阐明了关于ML NII $ _ {2} $多性性的争论，并阐明了层堆积引起的非共线自旋交换相互作用和磁性各向异性在厚度依赖性磁性中的作用。
A recent experiment reported type-II multiferroicity in monolayer (ML) NiI$_{2}$ based on a presumed spiral magnetic configuration (Spiral-B), which is, as we found here, under debate in the ML limit. Freestanding ML NiI$_{2}$ breaks its C$_{3}$ symmetry, as it prefers a striped antiferromagnetic order (AABB-AFM) along with an intralayer antiferroelectric (AFE) order. However, substrate confinement may preserve the C$_{3}$ symmetry and/or apply tensile strain to the ML. This leads to another spiral magnetic order (Spiral-$IV^X$), while 2L shows a different order (Spiral-$V^Y$) and Spiral-B dominates in thicker layers. Thus, three multiferroic phases, namely, Spiral-B+FE, Spiral-$IV^X$ +FE, Spiral-$V^Y$+FE, and an anti-multiferroic AABB-AFM+AFE one, show layer-thickness-dependent and geometry-dependent dominance, ascribed to competitions among thickness-dependent Kitaev, biquadratic, and Heisenberg spin-exchange interactions and single-ion magnetic anisotropy. Our theoretical results clarify the debate on the multiferroicity of ML NiI$_{2}$ and shed light on the role of layer-stacking-induced changes in noncollinear spin-exchange interactions and magnetic anisotropy in thickness-dependent magnetism.
