论文标题
带有伪螺旋间隙
Spin filtering in germanium/silicon core/shell nanowires with pseudo-helical gap
论文作者
论文摘要
具有较强自旋轨道相互作用的半导体可以表现出一个螺旋间隙，并带有磁场打开的自旋摩托明锁定。由于受拓扑保护的自旋摩托锁定，这种间隙是高度自旋选择性的，可用于自旋滤波。我们通过实验证明了在准球式P型锗/硅核/壳纳米线（NW）中具有这种自旋滤波效果，它具有伪螺旋间隙，而无需应用磁场。使用钴铁磁接触可实现NW的偏振孔自旋注入，并作为隧道屏障在NW上具有受控的天然氧化物。测量局部和非局部自旋阀效应是对螺旋间隙外NW的极化自旋转运的验证。我们通过用栅极扫描其化学电位，将NW电气调整到螺旋间隙中。在局部自旋阀几何形状中观察到具有三个电阻态的磁滞回路，这是螺旋间隙中自旋滤波的证据。
Semiconductors with strong spin-orbit interactions can exhibit a helical gap with spin-momentum locking opened by a magnetic field. Such a gap is highly spin selective as a result of a topologically protected spin-momentum locking, which can be used for spin filtering. We experimentally demonstrate such a spin filtering effect in a quasi-ballistic p-type germanium/silicon core/shell nanowire (NW), which possesses a pseudo-helical gap without the application of magnetic field. Polarized hole spin injection to the NW is achieved using cobalt ferromagnetic contacts with controlled natural surface oxide on the NW as a tunnel barrier. Local and nonlocal spin valve effects are measured as the verification of polarized spin transport in the NW outside the helical gap. We electrically tune the NW into the helical gap by scanning its chemical potential with a gate. A hysteresis loop with three resistance states is observed in the local spin valve geometry, as an evidence of spin filtering in the helical gap.
