Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei, 230031, China.
Science Island Branch of Graduate School, University of Science and Technology of China, Hefei, 230026, China.
Phys Chem Chem Phys. 2023 Feb 22;25(8):6461-6466. doi: 10.1039/d2cp05834k.
Spintronics is one of the main topics in condensed matter physics, in which half-metallicity and giant magnetoresistance are two important objects to achieve. In this work, we study the spin dependent transport properties of zigzag graphene nanoribbons (ZGNR) with asymmetric edge hydrogenation and different magnetic configurations using the non-equilibrium Green's function method combined with density functional calculations. Our results show that when the magnetic configurations of the electrodes change from parallel to antiparallel, the currents in the tunnel junction change substantially, resulting in a high conductance state and a low conductance state, with the tunnel magnetoresistance (TMR) ratio larger than 1 × 10% achieved. In addition, in the parallel magnetic configurations, an ideal bipolar spin filtering effect is observed, making it flexible to switch the spin polarity of current by reversing the bias direction. All these features originate from the spin semiconducting behavior of the asymmetrically hydrogenated ZGNRs. The findings suggest that asymmetric edge hydrogenation provides an important way to construct multi-functional spintronic devices with ZGNRs.
自旋电子学是凝聚态物理的主要研究课题之一，其中半金属性和巨磁电阻是实现的两个重要目标。在这项工作中，我们使用非平衡格林函数方法结合密度泛函计算研究了具有不对称边缘氢化和不同磁构型的锯齿型石墨烯纳米带（ZGNR）的自旋相关输运性质。我们的结果表明，当电极的磁构型从平行变为反平行时，隧道结中的电流发生了显著变化，导致出现高电导态和低电导态，实现了大于 1×10%的隧道磁电阻（TMR）比值。此外，在平行磁构型中，观察到了理想的双极性自旋过滤效应，可以通过反转偏置方向灵活地切换电流的自旋极性。所有这些特性都源于不对称氢化 ZGNR 的自旋半导体行为。研究结果表明，不对称边缘氢化为构建基于 ZGNR 的多功能自旋电子器件提供了重要途径。
