Khokhriakov Dmitrii, Karpiak Bogdan, Hoque Anamul Md, Zhao Bing, Parui Subir, Dash Saroj P
Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296, Göteborg, Sweden.
K.U. Leuven, 3001 Leuven, Belgium.
ACS Nano. 2020 Nov 24;14(11):15864-15873. doi: 10.1021/acsnano.0c07163. Epub 2020 Nov 2.
The utilization of large-area graphene grown by chemical vapor deposition (CVD) is crucial for the development of scalable spin interconnects in all-spin-based memory and logic circuits. However, the fundamental influence of the presence of multilayer graphene patches and their boundaries on spin dynamics has not been addressed yet, which is necessary for basic understanding and application of robust spin interconnects. Here, we report universal spin transport and dynamic properties in specially devised single layer, bilayer, and trilayer graphene channels and their layer boundaries and folds that are usually present in CVD graphene samples. We observe uniform spin lifetime with isotropic spin relaxation for spins with different orientations in graphene layers and their boundaries at room temperature. In all of the inhomogeneous graphene channels, the spin lifetime anisotropy ratios for spins polarized out-of-plane and in-plane are measured to be close to unity. Our analysis shows the importance of both Elliott-Yafet and D'yakonov-Perel' mechanisms with an increasing role of the latter mechanism in multilayer channels. These results of universal and isotropic spin transport on large-area inhomogeneous CVD graphene with multilayer patches and their boundaries and folds at room temperature prove its outstanding spin interconnect functionality, which is beneficial for the development of scalable spintronic circuits.
利用化学气相沉积（CVD）生长的大面积石墨烯对于基于全自旋的存储器和逻辑电路中可扩展自旋互连的发展至关重要。然而，多层石墨烯片及其边界的存在对自旋动力学的基本影响尚未得到解决，而这对于稳健自旋互连的基本理解和应用是必要的。在此，我们报告了在特别设计的单层、双层和三层石墨烯通道及其层边界和褶皱（这些通常存在于CVD石墨烯样品中）中的通用自旋输运和动力学特性。我们观察到在室温下，石墨烯层及其边界中不同取向的自旋具有各向同性自旋弛豫的均匀自旋寿命。在所有非均匀石墨烯通道中，垂直和平行极化自旋的自旋寿命各向异性比测量值接近1。我们的分析表明，埃利奥特 - 亚费特（Elliott - Yafet）机制和迪亚科诺夫 - 佩雷尔（D'yakonov - Perel'）机制都很重要，且后者机制在多层通道中的作用日益增加。这些关于大面积非均匀CVD石墨烯（具有多层片及其边界和褶皱）在室温下通用且各向同性自旋输运的结果证明了其出色的自旋互连功能，这有利于可扩展自旋电子电路的发展。
