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arXiv 2106.14062cond-mat.mes-hall
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线缺陷对硅烯纳米带带隙和输运性质的影响

Role of line defect in the bandgap and transport properties of silicene nanoribbons

Fei Wan, Xinru Wang, Yawen Guo, Jiayan Zhang, ZhengCheng Wen, Yuan Li

摘要:

利用紧束缚模型和非平衡格林函数方法(NEGF),研究了硅烯纳米晶体的能带结构和输运性质.由于线缺陷的影响,平坦子带向下或向上弯曲。自旋轨道耦合诱导量子自旋霍尔态。特别地,能带依赖于线缺陷与纳米晶边缘之间的距离。在位能量对两种缺陷组态能带谱的影响是不同的。对于情况1的缺陷组态,对于不同的在位能量,总是存在一个带隙。然而,可以通过改变情况2的缺陷配置的在位能量、亚晶格势和自旋轨道耦合来调制无带隙状态和带隙。因此,从亚晶格势、在位能和自旋轨道耦合对能带结构的综合影响可以很好地理解电导(包括零电导)的变化趋势.因此,利用亚晶格势、在位能量和自旋轨道耦合,可以简单有效地调节具有第二种缺陷结构的硅烯纳米晶体的输运性质.本研究对硅基器件的制备和输运特性的调控具有重要意义。

英文摘要:

By using the tight-binding model and non-equilibrium Green's function method (NEGF), we study the band structures and transport properties of a silicene nanoribbon with a line defect where a bulk energy gap is opened due to the sublattice symmetry breaking. The flat subband bends downwards or upwards due to the effect of the line defect. The spin-orbit coupling induces quantum spin Hall states. Especially, the energy band depends on the distance between the line defect and the edge of the nanoribbon. The effects of the on-site energies on the band spectra of the two defect configurations are different. There always exists one band gap for different on-site energies for the defect configuration of case 1. However, a gapless state and a band gap can be modulated by changing the on-site energy, the sublattice potential and spin-orbit couplings for the defect configuration of case 2. Accordingly, the variation trends of the conductance including zero conductance can be well understood in terms of the combined effect of the sublattice potential, the on-site energy and spin-orbit couplings on the band structures. Thus it is easy and effective to modulate the transport property of the silicene nanoribbon with the defect configuration of case 2 by utilizing the sublattice potential, the on-site energy and spin-orbit couplings. This study is of great significance for the fabrication and the modulation of the transport property of silicene-based devices.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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