We have computationally demonstrated a new method for generating pure spin current with the photogalvanic effect (PGE) by constructing transport junctions using h-BN/graphene/h-BN van der Waals (vdW) heterostructure leads. It has been observed that the pure spin current without any accompanying charge current induced by the PGE can consistently be obtained, regardless of photon energy and polarization/helicity angle, as well as the specific type of polarization (linear, circular, or elliptical). The mechanism lies in the structural inversion symmetry and real space spin polarization antisymmetry of the junctions. We also found that pure spin current can be generated whether we decrease or increase the interlayer distance by applying compressive or tensile strain to the h-BN/graphene/h-BN vdW vertical heterostructure leads. Additionally, by increasing the h-BN sheets on both sides of the graphene nanoribbons for the two leads, we observed large spin splitting and were able to generate pure spin current. These findings provide a new approach for achieving pure spin current in graphene nanoribbons and highlight the significance of vdW heterostructures in designing spintronic devices.

中文翻译：

---

在 h-BN/石墨烯/h-BN 范德华垂直异质结构中产生具有光电流效应的纯自旋电流


我们已经通过计算展示了一种通过使用 h-BN/石墨烯/h-BN 范德华 （vdW） 异质结构引线构建输运结点来产生具有光电流效应 （PGE） 的纯自旋电流的新方法。据观察，无论光子能量和偏振/螺旋角如何，以及特定类型的偏振（线性、圆形或椭圆形），都可以始终如一地获得由 PGE 感应的任何伴随电荷电流的纯自旋电流。其机制在于结的结构反转对称性和实空间自旋极化反对称性。我们还发现，无论我们通过对 h-BN/石墨烯/h-BN vdW 垂直异质结构引线施加压缩或拉伸应变来减少或增加层间距离，都可以产生纯自旋电流。此外，通过增加两条引线的石墨烯纳米带两侧的 h-BN 片材，我们观察到了大的自旋分裂，并能够产生纯自旋电流。这些发现为在石墨烯纳米带中实现纯自旋电流提供了一种新方法，并突出了 vdW 异质结构在设计自旋电子器件中的重要性。