Using the transfer matrix method, spin- and valley-dependent electron transport properties modulated by the velocity barrier were studied in the normal/ferromagnetic/normal monolayer MoS₂ quantum structure. Based on Snell’s Law in optics, we define the velocity barrier as ξ = v₂/v₁ by changing the Fermi velocity of the intermediate ferromagnetic region to obtain a deflection condition during the electron transport process in the structure. The results show that both the magnitude and the direction of spin- and valley-dependent electron polarization can be regulated by the velocity barrier. − 100% polarization of spin- and valley-dependent electron can be achieved for ξ > 1, while 100% polarization can be obtained for ξ < 1. Furthermore, it is determined that perfect spin and valley transport always occur at a large incident angle. In addition, the spin- and valley-dependent electron transport considerably depends on the length k_FL and the gate voltage U(x) of the intermediate ferromagnetic region. These findings provide an effective method for designing novel spin and valley electronic devices.

中文翻译：

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速度势垒对单层MoS 2量子结构中大量Dirac电子传输的影响

使用转移矩阵方法，研究了在正常/铁磁/正常单层MoS ₂量子结构中受速度势垒调节的自旋和谷依赖的电子传输性质。根据光学的斯涅尔定律，通过改变中间铁磁区的费米速度以获得结构中电子传输过程中的偏转条件，将速度势垒定义为ξ = v ₂ / v ₁。结果表明，自旋和谷依赖的电子极化的大小和方向都可以通过速度屏障来调节。-自旋和谷依赖性电子的100％极化可用于实现ξ大于1时，对于ξ <1可以获得100％的极化。此外，可以确定，总是在大入射角处发生了完美的自旋和谷值传输。另外，取决于自旋和谷的电子传输在很大程度上取决于长度k _F L和中间铁磁区域的栅极电压U（x）。这些发现为设计新颖的自旋谷电子器件提供了有效的方法。