Molecular-scale magnetic devices have attracted great attention of research in recent years. In this work, by using the non-equilibrium Green’s function (NEGF) method in combination with density functional theory (DFT), we investigated the spin transport properties of manganese phthalocyanine based spintronic devices constructed by a mononuclear manganese phthalocyanine (MnPc) or binuclear manganese phthalocyanine (Mn₂Pc₂) sandwiched between two zigzag-edge graphene nanoribbon (zGNR) electrodes. The calculation results show that both MnPc and Mn₂Pc₂ devices are good spin filters manifesting excellent spin filtering effect, which is originated from the distinct difference in the energy alignments of the spin-up and spin-down molecular electronic states with respect to the Fermi energy ($E_{\mathrm{F}}$) of zGNR electrodes. More interestingly, the spin polarization of the tunneling electrons through the devices is intimately opposite to that of Mn atom(s). Specifically, for a spin-up polarization of Mn in the devices, almost only the spin-down electrons are allowed to go through the device, and vice versa. In addition, spin filtering efficiency (SFE) of the devices is evidently enhanced in Mn₂Pc₂ devices in comparison with that of the MnPc devices, of which the value of SFE can reach almost 100%. This enhancement is attributed to the fact that the spin electronic states of Mn₂Pc₂ devices are closer to $E_{\mathrm{F}}$ and there is a weaker localization in their spatial distributions induced by the external bias voltage. Furthermore, both MnPc and Mn₂Pc₂ devices can act as NOT logic gates by taking the spin polarization characteristics of Mn atom(s) and current of devices as input and output signals, respectively. This work demonstrates that mononuclear MnPc and binuclear Mn₂Pc₂ molecules have potential applications in designing multifunctional spintronic single-molecule devices.

近年来，分子尺度的磁性器件引起了研究的极大关注。在这项工作中，通过使用非平衡格林函数（NEGF）方法结合密度泛函理论（DFT），我们研究了由单核锰酞菁（MnPc）或双核锰构建的基于锰酞菁的自旋电子器件的自旋输运特性酞菁（Mn ₂ Pc ₂ ）夹在两个锯齿形边缘石墨烯纳米带（zGNR）电极之间。计算结果表明，MnPc 和 Mn ₂ Pc ₂ 器件是良好的自旋过滤器，表现出优异的自旋过滤效果，这是由于自旋向上和自旋向下分子电子态相对于费米能量的能量排列存在明显差异（${乙}_{\mathrm{F}}$) zGNR 电极。更有趣的是，穿过器件的隧道电子的自旋极化与 Mn 原子的自旋极化密切相反。具体而言，对于器件中 Mn 的自旋向上极化，几乎只有自旋向下的电子被允许通过器件，反之亦然。此外，与MnPc器件相比，Mn ₂ Pc ₂器件的自旋过滤效率(SFE)明显提高，其中SFE值几乎可以达到100%。这种增强归因于 Mn ₂ Pc ₂器件的自旋电子态更接近于${乙}_{\mathrm{F}}$并且在外部偏置电压引起的空间分布中存在较弱的局部化。此外，MnPc和Mn ₂ Pc ₂器件都可以通过将Mn原子的自旋极化特性和器件的电流分别作为输入和输出信号来充当非逻辑门。这项工作表明单核MnPc 和双核Mn ₂ Pc ₂分子在设计多功能自旋电子单分子器件方面具有潜在的应用。