We investigate the photovoltaic behaviors of magnetic graphene interconnect junctions, which are constructed by zigzag graphene nanoribbons (ZGNRs), with the aim to produce pure spin current by photogalvanic effect (PGE). Two kinds of interconnect junctions are designed by connecting two 6-ZGNR with a carbon hexagon (C6) and a carbon tetragon (C4), respectively. It is found that zero charge current is produced under irradiation of light in both structures due to the presence of spatial inversion symmetry. Nevertheless, behind the zero charge current, net pure spin current is produced in the structure with a C6, but not in the structure with a C4. This difference originates from their different edge state distribution and different spatial inversion symmetry of the spin density. However, interestingly, local edge pure spin current can be obtained in both structures. More importantly, the pure spin current generation is independent of the photon energy, polarization type or polarization angle, suggesting a robust way of generating pure spin current with PGE and new possibility of graphene’s applications in spintronics.

中文翻译：

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在石墨烯互连结中产生具有光电流效应的纯自旋电流

我们研究了由之字形石墨烯纳米带（ZGNRs）构造的磁性石墨烯互连结的光伏行为，旨在通过光电效应（PGE）产生纯自旋电流。通过分别将两个6-ZGNR与一个碳六边形（C6）和一个碳四边形（C4）连接来设计两种互连结。发现由于空间反转对称的存在，在两种结构的光照射下产生零电荷电流。但是，在零电荷电流之后，在具有C6的结构中会产生净纯自旋电流，而在具有C4的结构中不会产生。这种差异源于它们不同的边缘状态分布和自旋密度的不同空间反演对称性。但是，有趣的是，两种结构均可获得局部边缘纯自旋电流。更重要的是，纯自旋电流的产生与光子能量，极化类型或极化角无关，这表明使用PGE产生纯自旋电流的可靠方法以及石墨烯在自旋电子学中的新应用可能性。