Scuola Internazionale Superiore di Studi Avanzati (SISSA) and Democritos National Simulation Center, Consiglio Nazionale delle Ricerche, Istituto Officina dei Materiali (CNR-IOM) , Via Bonomea 265 , 34136 Trieste , Italy.
Nano Lett. 2018 Mar 14;18(3):2158-2164. doi: 10.1021/acs.nanolett.8b00453. Epub 2018 Feb 28.
We demonstrate that hexagonal graphene nanoflakes with zigzag edges display quantum interference (QI) patterns analogous to benzene molecular junctions. In contrast with graphene sheets, these nanoflakes also host magnetism. The cooperative effect of QI and magnetism enables spin-dependent quantum interference effects that result in a nearly complete spin polarization of the current and holds a huge potential for spintronic applications. We understand the origin of QI in terms of symmetry arguments, which show the robustness and generality of the effect. This also allows us to devise a concrete protocol for the electrostatic control of the spin polarization of the current by breaking the sublattice symmetry of graphene, by deposition on hexagonal boron nitride, paving the way to switchable spin filters. Such a system benefits from all of the extraordinary conduction properties of graphene, and at the same time, it does not require any external magnetic field to select the spin polarization, as magnetism emerges spontaneously at the edges of the nanoflake.
我们证明了具有锯齿边缘的六方石墨烯纳米片显示出类似于苯分子结的量子干涉 (QI) 图案。与石墨烯片不同，这些纳米片还具有磁性。QI 和磁性的协同作用使自旋相关的量子干涉效应得以实现，导致电流的自旋极化几乎完全，为自旋电子学应用提供了巨大的潜力。我们根据对称论证理解了 QI 的起源，这表明了该效应的稳健性和普遍性。这也使我们能够通过打破石墨烯的子晶格对称性，通过在六方氮化硼上沉积来设计一个具体的静电控制电流自旋极化的方案，为可切换的自旋滤波器铺平了道路。这样的系统受益于石墨烯所有非凡的传导特性，同时，它不需要任何外部磁场来选择自旋极化，因为磁性在纳米片的边缘自发出现。
