Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322, USA.
Phys Chem Chem Phys. 2019 Sep 18;21(36):19764-19771. doi: 10.1039/c9cp03786a.
Among the diversity of new materials, two-dimensional crystal structures have been attracting significant attention from the broad scientific community due to their promising applications in nanoscience. In this study we predict a novel two-dimensional ferromagnetic boron material, which has been exhaustively studied with DFT methods. The relaxed structure of the 2D-B6 monolayer consists of slightly flattened octahedral units connected with 2c-2e B-B σ-bonds. The calculated phonon spectrum and ab initio molecular dynamics simulations reveal the thermal and dynamical stability of the designed material. The calculation of the mechanical properties indicate a relatively high Young's modulus of 149 N m-1. Moreover, the electronic structure indicates the metallic nature of the 2D-B6 sheets, whereas the magnetic moment per unit cell is found to be 1.59 μB. The magnetism in the 2D-B6 monolayer can be described by the presence of two unpaired delocalized bonding elements inside every distorted octahedron. Interestingly, the nature of the magnetism does not lie in the presence of half-occupied atomic orbitals, as was shown for previously studied magnetic materials based on boron. We hope that our predictions will provide promising new ideas for the further fabrication of boron-based two-dimensional magnetic materials.
在众多新型材料中，二维晶体结构因其在纳米科学中的应用前景而受到广泛关注。在本研究中，我们通过 DFT 方法对一种新型二维铁磁硼材料进行了详尽的研究。二维 B6 单层的弛豫结构由略微扁平的八面体单元通过 2c-2e B-B σ 键连接而成。计算得到的声子谱和第一性原理分子动力学模拟表明了设计材料的热和动力学稳定性。力学性能的计算表明，其杨氏模量相对较高，为 149 N m-1。此外，电子结构表明二维 B6 片具有金属性质，而每个单胞的磁矩为 1.59 μB。在二维 B6 单层中，每个扭曲八面体内部存在两个未配对的离域成键元素，从而表现出磁性。有趣的是，这种磁性的本质不在于占据一半的原子轨道，这与之前研究的基于硼的磁性材料不同。我们希望我们的预测将为进一步制备基于硼的二维磁性材料提供有前景的新想法。
