论文标题
形状拓扑绝缘子纳米线中的磁转运理论
Theory of magnetotransport in shaped topological insulator nanowires
论文作者
论文摘要
我们表明，形状的拓扑绝缘子（TI）纳米线，即它们的横截面半径沿着电线长度变化，当浸入同质同轴磁场中时，可以将其调谐到许多不同的传输方案中。这与经过恒定的横截面的广泛研究的管状纳米线相反，并且是由于对狄拉克表面载体的磁性约束而引起的。在扁平的2D系统中，这种限制需要非均匀的磁场，而对于$ b \ sim \，1 $ t的标准尺寸均匀域的形状纳米线就足够了。我们投入了最近的工作[Kozlovsky等人，物理学。莱特牧师。 124，126804（2020）]进入更广泛的上下文，并将其扩展到具有任意径向谱的轴向对称的线几何形状。哑铃形ti纳米线被用作通过收缩进行运输的范式示例，并显示为五个不同的运输方式：（i）电导步骤，（ii）谐振变速器，（iii）电流抑制，（iv）库仑（iv）库仑封锁和（v）（v）通过triple量子dot传输。通过调节同轴磁场的强度，可以实现在机制之间的切换，并且不需要严格的轴向对称性。因此，应该在用可用的实验技术制造的Ti纳米线中观察到它。
We show that shaped topological insulator (TI) nanowires, i.e. such that their cross-section radius varies along the wire length, can be tuned into a number of different transport regimes when immersed in a homogeneous coaxial magnetic field. This is in contrast with widely studied tubular nanowires with constant cross-section, and is due to magnetic confinement of Dirac surface carriers. In flat 2D systems such a confinement requires non-homogeneous magnetic fields, while for shaped nanowires of standard size homogeneous fields of the order of $B\sim\,1$T are sufficient. We put recent work [Kozlovsky et al., Phys. Rev. Lett. 124, 126804 (2020)] into broader context and extend it to deal with axially symmetric wire geometries with arbitrary radial profile. A dumbbell-shaped TI nanowire is used as a paradigmatic example for transport through a constriction and shown to be tunable into five different transport regimes: (i) conductance steps, (ii) resonant transmission, (iii) current suppression, (iv) Coulomb blockade, and (v) transport through a triple quantum dot. Switching between regimes is achieved by modulating the strength of a coaxial magnetic field and does not require strict axial symmetry of the wire cross-section. As such, it should be observable in TI nanowires fabricated with available experimental techniques.
