Fe3GeTe2纳米带的结构稳定性、磁电子性质及调控效应  

Structure stability, magneto-electronic properties, and modulation effects of Fe3GeTe2 nanoribbons

作　　者：韩佳凝 范志强 张振华[1] Han Jia-Ning;Fan Zhi-Qiang;Zhang Zhen-Hua(Hunan Provincial Key Laboratory of Flexible Electronic Materials Genome Engineering, Changsha University of Science and Technology, Changsha 410114, China)

机构地区：[1]长沙理工大学柔性电子材料基因工程湖南省重点实验室

出　　处：《物理学报》2019年第20期301-309,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61771076,11674039)资助的课题~~

摘　　要：Fe3GeTe2是目前发现的少数几种二维铁磁材料之一.基于密度泛函理论的第一性原理方法,我们对二维Fe3GeTe2剪裁而成的纳米带NR(n)的结构稳定性和磁电子学特性进行了详细研究.计算的结合能及分子动力学模拟表明纳米带的结构是非常稳定的.纳米带呈现较大的磁矩及磁化能,这说明它们具有较高的磁稳定性.特别是在费米能级上,纳米带具有较高的自旋极化率(SPF),如NR(5)的SPF可达100%.同时发现SPF随纳米带宽度变化有明显的奇偶振荡效应,且纳米带的SPF比2维单层的情况有明显优势.此外,拉伸效应的计算结果表明,应变可以灵活地调节纳米带的SPF使其在接近零值和85.6%之间变化,这意味着可设计一个机械开关来控制低偏压下的自旋输运,使其可逆地工作在高自旋极化与无自旋极化之间.Fe3GeTe2 monolayer is one of the currently fabricated 2-dimensional(2D) ferromagnetic materials. Based on the first principle of density functional theory, we here study the structural stability and magneto-electronic properties of nanoribbons NR(n) obtained by cutting 2D Fe3GeTe2. The calculated binding energy and molecular dynamics simulation results identify that nanoribbons are rather stable. The large magnetic moment and magnetized energy prove the extremely high magnetism stability for NR(n). Moreover, with the increase of the width, the magnetic moment of the nanoribbons generally increases, and gradually tends to a stable value.In particular, the nanoribbons possess a high spin polarization efficiency at the Fermi level(SPF). For example,the SPF for NR(5) is up to 100%. With the width variation of the nanoribbons, the SPF has a significant oddeven oscillating effect, that is, the spin-polarization of the odd nanoribbons is higher than that of the adjacent even nanoribbons, especially when the width is in the range of n ≤ 12. This means that the a-spin and b-spin are quite different in the density of states at the Fermi level when the width is odd or even. This may be caused by the difference of the quantum confinement effect for the odd or even nanoribbons, respectively. Meanwhile,when the width of the nanoribbons is wide enough, the odd-even oscillation effect of the spin polarizability is stabilized in a relatively small range, and the nanoribbons finally tend to be 2D Fe3GeTe2 monolayer. The nanoribbons have an obvious advantage on SPF over the 2D Fe3GeTe2 monolayer. In addition, the calculation of the strain effect demonstrates that the strain can flexibly tune the SPF varying from approximately zero to 85.6%, and the SPF reaches a maximum of 85.6% at a stretch of 4%, which is a fairly high value;then reaches a minimum at a stretch of 8%, almost being zero, which means that a mechanical switch can be designed to control the low-bias spin transition, allowing it work between high spin polarization an

关 键 词：Fe3GeTe2纳米带 磁电子学特性 自旋极化 拉伸效应 

分 类 号：TB383.1[一般工业技术—材料科学与工程]