Quantum-Phase Electronics Center and Department of Applied Physics, The University of Tokyo, Tokyo 113-8656, Japan.
Nano Lett. 2012 May 9;12(5):2212-6. doi: 10.1021/nl204012c. Epub 2012 Apr 6.
Taking advantage of ultrahigh electric field generated in electric-double-layer transistors (EDLTs), we investigated spin-orbit interaction (SOI) and its modulation in epitaxial trilayer graphene. It was found in magnetotransport that the dephasing length L(φ) and spin relaxation length L(so) of carriers can be effectively modulated with gate bias. As a direct result, SOI-induced weak antilocalization (WAL), together with a crossover from WAL to weak localization (WL), was observed at near-zero magnetic field. Interestingly, among existing localization models, only the Iordanskii-Lyanda-Geller-Pikus theory can successfully reproduce the obtained magnetoconductance well, serving as evidence for gate tuning of the weak but distinct SOI in graphene. Realization of SOI and its large tunability in the trilayer graphene EDLTs provides us with a possibility to electrically manipulate spin precession in graphene systems without ferromagnetics.
利用电双层晶体管（EDLTs）中产生的超高电场，我们研究了外延三层石墨烯中的自旋轨道相互作用（SOI）及其调制。在磁输运中发现，载流子的退相长度 L(φ) 和自旋弛豫长度 L(so) 可以通过栅极偏压有效地进行调制。作为直接结果，在近零磁场下观察到了 SOI 诱导的弱反局域（WAL），以及从 WAL 到弱局域（WL）的交叉。有趣的是，在现有的局域化模型中，只有 Iordanskii-Lyanda-Geller-Pikus 理论才能很好地再现所得到的电导，这为在石墨烯中对弱但明显的 SOI 进行栅极调谐提供了证据。在三层石墨烯 EDLTs 中实现 SOI 及其大的可调性为我们提供了一种可能性，即在没有铁磁体的情况下，电操控石墨烯系统中的自旋进动。
