We have demonstrated a Si-based bottom-gate-type spin metal-oxide-semiconductor field-effect transistor (spin MOSFET) with an electron inversion channel at room temperature and showed the enhancement of the room-temperature effective spin diffusion length by “spin drift”. Our spin MOSFET was fabricated on a (001)-oriented silicon-on-insulator (SOI) substrate with a p-type ultrathin (8 nm) Si layer, in which the channel length was 1.0 μm, the spin injector/detector electrodes were ferromagnetic multilayer (from top to bottom) Fe(4nm)/Mg(1nm)/MgO(1nm) tunnel junctions, and a 200-nm-thick buried oxide layer was used for the gate dielectric. Using various gate electric fields and source-drain electron currents, two types of spin-dependent transport signals were measured: spin-valve signals with an inplane magnetic field and Hanle signals with an out-of-plane magnetic field. Clear Hanle signals and spin-valve signals were obtained for various bias conditions. We analyzed the Hanle signals and the change of the spin-valve signals based on our original formulas that take into account the distribution of the lateral electric field along the electron transport, and revealed that the spin drift can enhance the effective spin diffusion length by the lateral electric field parallel to the electron transport in the inversion channel. The effective spin diffusion length becomes 3-13 times larger than the intrinsic spin diffusion length λS = 0.89 μm owing to the increase in the lateral electric field. It was confirmed that the spin drift is very useful to achieve larger spin-valve signals in spin MOSFETs with an electron inversion channel.

中文翻译：

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具有反转通道的硅基自旋 MOSFET 中室温有效自旋扩散长度的增强


我们展示了一种室温下具有电子反转沟道的硅基底栅型自旋金属氧化物半导体场效应晶体管（自旋MOSFET），并展示了通过“自旋”技术增强了室温有效自旋扩散长度。漂移”。我们的自旋MOSFET是在具有p型超薄（8 nm）Si层的（001）取向绝缘体上硅（SOI）衬底上制造的，其中沟道长度为1.0 μm，自旋注入器/探测器电极为铁磁多层（从上到下）Fe(4nm)/Mg(1nm)/MgO(1nm)隧道结，栅极电介质采用200nm厚的埋氧化层。使用各种栅极电场和源极-漏极电子电流，测量了两种类型的自旋相关传输信号：具有面内磁场的自旋阀信号和具有面外磁场的Hanle信号。在各种偏置条件下获得了清晰的 Hanle 信号和旋转阀信号。我们根据原始公式考虑了横向电场沿电子传输的分布，分析了 Hanle 信号和自旋阀信号的变化，并揭示了自旋漂移可以通过以下方式增强有效自旋扩散长度：与反转通道中的电子传输平行的横向电场。由于横向电场的增加，有效自旋扩散长度变得比本征自旋扩散长度λS = 0.89 μm大3-13倍。事实证明，自旋漂移对于在具有电子反转通道的自旋 MOSFET 中实现更大的自旋阀信号非常有用。