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利用基于密度泛函理论的第一性原理计算方法, 研究了Se边用H饱和、In边用各种非金属元素 X( X= H, B, N, P, F和Cl)端接的锯齿型InSe纳米带(H-ZN(7)- X)的几何结构、磁电子特性及应变效应. 计算的形成能和Forcite退火模拟表明H-ZN(7)- X具有稳定的几何结构. F和Cl端接时, 纳米带具有和H端接时类似的磁金属性质. N端接时, 纳米带磁性最强. 但B和P端接使得纳米带边缘的磁性完全消失. 特别是, 我们发现外加的机械应变可以增强H-ZN(7)-N磁稳定性, 并且有效地调节费米能级处的自旋极化率(SP), 能在0—92%之间变化, 这意味着可设计机械开关来控制低偏压下的自旋输运. 应变调制机制与应变诱导的键长变化导致不成对的电子的重新分布或消失有关. N-ZN(7)-N的磁性主要来源于In, Se及N原子的p轨道, 这对于研发非过渡金属磁性材料有重要意义.Employing the first-principles calculation based on the density functional theory, the geometries, magneto-electronicproperties, and strain effects of the zigzag-edged InSe nanoribbons with the Se-edge saturated by H atoms and In-edge terminated by various non-metallic elements X( X= H, B, N, P, F and Cl) are studied. The calculated formation energy and Forcite annealing simulations show that the H-ZN(7)-X has a stable geometry. For F- and Cl- terminated ribbons, they have a magnetic metallic property similar to that in the case of H termination, and for the N termination the nanoribbon has the strongest magnetic property. However, the B and P terminations cause the magnetic properties at the ribbon edge to completely disappear, particularly when the mechanical strain is applied. The magnetic stability of H-ZN(7)-N is enhanced, and the spin polarization efficiency (SP) at the Fermi level can be effectively modulated in a range from zero to 92%, which means that it is possible to design a mechanical switch for controlling the spin transport at low bias. The strain modulating mechanism is related to the fact that the variation of strain-induced bond length leads the unpaired electrons to be redistributed or disappear. The magnetic properties of N-ZN(7)-N are mainly derived from the porbitals of In, Se and N atoms, thus it is very important to develop non-transition metal magnetic materials.
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Structure EM µ(InL) µ(SeL) µ(X) M SP H-ZN(7)-H 7.95 0.15 0.21 0.07 0.47 43.0% B-ZN(7)-B 0 0 0 0 0 0% H-ZN(7)-N 78.32 0.02 0.10 0.52 0.632 55.6% H-ZN(7)-P 0 0 0 0 0 0% H-ZN(7)-F 8.82 0.14 0.25 0.03 0.44 38.8% H-ZN(7)-Cl 8.70 0.15 0.25 0.05 0.47 39.5% Structure EEF(ribbon) dX-X d0 d1 d2 d3 H-ZN(7)-H –3.12 3.93 1.72 2.83 2.60 2.57 H-ZN(7)-B –4.25 1.85 2.37 3.02 2.57 2.62 H-ZN(7)-N –5.47 3.90 2.12 2.75 2.60 2.66 H-ZN(7)-P –4.69 3.83 2.66 2.86 2.66 2.59 H-ZN(7)-F –4.86 3.93 1.72 2.82 2.60 2.57 H-ZN(7)-Cl –3.82 3.94 2.16 2.82 2.61 2.57 -
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