Zhou Jian, Jena Puru
Physics Department, Virginia Commonwealth University , Richmond, Virginia 23284, United States.
J Phys Chem Lett. 2017 Dec 7;8(23):5764-5770. doi: 10.1021/acs.jpclett.7b02507. Epub 2017 Nov 14.
Two-dimensional group VI transition-metal dichalcogenides (TMDs) provide a promising platform to encode and manipulate quantum information in the valleytronics. However, the two valleys are energetically degenerate, protected by time-reversal symmetry (TRS). To lift this degeneracy, one needs to break the TRS by either applying an external magnetic field or using a magnetic rare-earth oxide substrate. Here, we predict a different strategy to achieve this goal. We propose that the ferromagnetic group V TMD monolayer, in which the TRS is intrinsically broken, can produce a larger valley and spin splitting. A polarized ZnS(0001) surface is also used as a substrate, which shifts the valleys to the low-energy regime (near the Fermi level). Moreover, by calculating its collective electronic excitation behaviors, we show that such a system hosts a giant valley polarized terahertz plasmonics. Our results demonstrate a new way to design and use valleytronic devices, which are both fundamentally and technologically significant.
二维第VI族过渡金属二硫属化物（TMDs）为在谷电子学中编码和操纵量子信息提供了一个很有前景的平台。然而，这两个谷在能量上是简并的，受时间反演对称性（TRS）保护。为了消除这种简并，需要通过施加外部磁场或使用磁性稀土氧化物衬底来打破TRS。在此，我们预测了一种实现这一目标的不同策略。我们提出，铁磁第V族TMD单层，其TRS本质上被打破，能够产生更大的谷和自旋分裂。极化的ZnS(0001)表面也被用作衬底，它将谷转移到低能区（靠近费米能级）。此外，通过计算其集体电子激发行为，我们表明这样一个系统拥有巨大的谷极化太赫兹等离子体激元。我们的结果展示了一种设计和使用谷电子学器件的新方法，这在基础和技术层面都具有重要意义。
