Li Xiaobo, Li Yun, Zhang Xiaojiao, Long Mengqiu, Zhou Guanghui
Hunan Key Laboratory of Super-Microstructure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha, 410083, China.
Physical Science and Technology College, Yichun University, Yichun, 336000, China.
Nanoscale Res Lett. 2019 Aug 28;14(1):299. doi: 10.1186/s11671-019-3133-5.
Since the rapid development of theoretical progress on the two-dimensional graphyne nanoribbons and nanojunctions, here we investigate the electronic band structures and transport properties for the junctions based on armchair-edged γ-graphyne nanoribbons (AγGYNRs) with asymmetrically nitrogen (N)-substituting in the central carbon hexagon. By employing first-principles calculation, our computational results imply that the number and the location of single or double N-doping can efficiently modulate the electronic energy band, and the N-doping hexagonal rings in the middle of the junction play a vital role in the charge transport. In specific, the effect of negative difference resistance (NDR) is observed, in which possesses the biggest peak to valley ratio reaching up to 36.8. Interestingly, the N-doped junction with longer molecular chain in the central scattering region can induce a more obvious NDR behavior. The explanation of the mechanism in the microscopic level has suggested that the asymmetrically N-doped junction by introducing a longer molecular chain can produce a more notable pulse-like current-voltage dependence due to the presence of a transporting channel within the bias window under a higher bias voltage. In addition, when the spin injection is considered, an intriguing rectifying effect in combination with NDR is available, which is expected to be applied in future spintronic devices.
自从二维石墨炔纳米带和纳米结的理论进展迅速发展以来，在此我们研究基于扶手椅边缘γ-石墨炔纳米带（AγGYNRs）且在中心碳六边形中具有不对称氮（N）取代的结的电子能带结构和输运性质。通过采用第一性原理计算，我们的计算结果表明单重或双重N掺杂的数量和位置能够有效地调制电子能带，并且结中间的N掺杂六边形环在电荷输运中起着至关重要的作用。具体而言，观察到了负微分电阻（NDR）效应，其具有高达36.8的最大峰谷比。有趣的是，在中心散射区域具有更长分子链的N掺杂结能够诱导出更明显的NDR行为。微观层面的机理解释表明，通过引入更长的分子链，不对称N掺杂结在更高偏置电压下由于在偏置窗口内存在输运通道而能够产生更显著的脉冲状电流-电压依赖性。此外，当考虑自旋注入时，会出现一种与NDR相结合的有趣的整流效应，有望应用于未来的自旋电子器件中。
