Abstract Graphene and graphyne hold great potential for spintronic device applications due to their exceptionally good electrical and mechanical properties in the pristine form. Recently, considering these 2D carbon allotropes have similar bond lengths and unit cell shapes, ensuring a perfectly matched interface between them and construction of graphene/graphyne heterojunctions feasible. To this end, we study the spin-charge transport properties for monolayer graphene/graphyne zigzag-edged nanoribbon heterojunctions by employing the ab initio calculations, where two types of γ- and (6,6,12)-graphynes are considered, respectively. Our important result here is that these heterojunctions can exhibit an interesting variation of magnetoresistane by applying ferromagnetic stripes or external magnetic fields onto the ribbons to initially orient their spin configuration. Specifically, the magnetoresistance ratio can be up to 104% for graphene/γ-graphyne heterojunction, but only 300% for the graphene/(6,6,12)-graphyne one. In addition, the effects of spin-filtering and negative differential resistance are also observed in those heterojunctions. The maximum of spin filtering efficiency can be up to 99%. The mechanisms are revealed and analyzed by the connection of these effects to the evolution of the spin-resolved electron transmission spectra and pathways around the Fermi level at zero bias.

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石墨烯/石墨烯锯齿形边缘纳米带异质结的自旋电荷传输特性：第一性原理研究

摘要 石墨烯和石墨炔在自旋电子器件应用中具有巨大的潜力，因为它们在原始形式下具有非常好的电气和机械性能。最近，考虑到这些二维碳同素异形体具有相似的键长和晶胞形状，确保它们之间完美匹配的界面和石墨烯/石墨烯异质结的构建可行。为此，我们通过从头算计算研究了单层石墨烯/石墨烯锯齿形边缘纳米带异质结的自旋电荷传输特性，其中分别考虑了两种类型的 γ- 和 (6,6,12)-石墨烯。我们在这里的重要结果是，这些异质结可以通过将铁磁条或外部磁场施加到带上以初始定向它们的自旋配置来展示磁阻的有趣变化。具体来说，石墨烯/γ-石墨烯异质结的磁阻比可高达104%，但石墨烯/(6,6,12)-石墨烯异质结的磁阻比仅为300%。此外，在这些异质结中也观察到自旋过滤和负微分电阻的影响。自旋过滤效率最高可达99%。通过将这些效应与自旋分辨电子传输光谱的演变和零偏压下费米能级附近的路径联系起来，揭示和分析这些机制。石墨烯/γ-石墨烯异质结的磁阻比可高达104%，而石墨烯/(6,6,12)-石墨烯异质结的磁阻比仅为300%。此外，在这些异质结中也观察到自旋过滤和负微分电阻的影响。自旋过滤效率最高可达99%。通过将这些效应与自旋分辨电子传输光谱的演变和零偏压下费米能级附近的路径联系起来，揭示和分析这些机制。石墨烯/γ-石墨烯异质结的磁阻比可高达104%，而石墨烯/(6,6,12)-石墨烯异质结的磁阻比仅为300%。此外，在这些异质结中也观察到自旋过滤和负微分电阻的影响。自旋过滤效率最高可达99%。通过将这些效应与自旋分辨电子传输光谱的演变和零偏压下费米能级附近的路径联系起来，揭示和分析这些机制。