论文标题
相对于散装金属BI2SE3和构造BI2TE2SE拓扑绝缘子薄片的相反电流引起的自旋极化
Opposite current-induced spin polarizations in bulk-metallic Bi2Se3 and bulk-insulating Bi2Te2Se topological insulator thin flakes
论文作者
论文摘要
3D拓扑绝缘子（TIS）的最基本和外来性质之一是其拓扑表面状态（TSS）的自旋摩托锁（SML），有望在未来的Spintronics中使用潜在的应用。然而，其他可能的传导通道，例如具有强大的rashba型自旋轨道相互作用（SOI）和可能具有旋转厅效应（SHE）的庞大的旋转轨道相互作用（SOI）的微不足道的二维电子气体（2DEG），可以在3D TIS中共存，从而确定当前诱导的旋转极化（CISP）的确定起源。在这项工作中，我们直接使用旋转电位仪直接比较了构造BI2TE2SE（BTS221）和散装金属金2SE3薄片之间的CISP。在散装绝缘BTS221中，观察到的CISP具有与TSS SML的预期螺旋性一致的符号，但与其计算出的散装旋转霍尔电导率（SHC）相反。但是，与BTS221相比，在散装金属BI2SE3中观察到了相反的CISP，而是与Rashba-Edelstein效应的期望一致，对带弯曲的诱导的2DEG和散装旋转厅效应（SHE）一致。我们的结果提供了一种电气方式，可以将TSS与3D TI上的自旋传输测量中的其他可能导电通道区分开，并为电荷旋转转换设备中的潜在应用开放方式。
One of the most fundamental and exotic properties of 3D topological insulators (TIs) is spin-momentum-locking (SML) of their topological surface states (TSSs), promising for potential applications in future spintronics. However, other possible conduction channels, such as a trivial two-dimensional electron gas (2DEG) with strong Rashba type spin-orbit interaction (SOI) and bulk conducting states that may possess a spin Hall effect (SHE), can coexist in 3D TIs, making determining the origin of the current induced spin polarization (CISP) difficult. In this work, we directly compared the CISP between bulk-insulating Bi2Te2Se (BTS221) and bulk-metallic Bi2Se3 thin flakes using spin potentiometry. In the bulk insulating BTS221, the observed CISP has a sign consistent with the expected helicity of the SML of the TSS, but an opposite sign to its calculated bulk spin Hall conductivity (SHC). However, compared to BTS221, an opposite CISP is observed in the bulk metallic Bi2Se3, consistent instead with both the expectations of its Rashba-Edelstein effect of the band-bending induced 2DEG and bulk spin Hall Effect (SHE). Our results provide an electrical way to distinguish the TSS from other possible conducting channels in spin transport measurements on 3D TIs, and open ways for the potential applications in charge-spin conversion devices.
