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.

中文翻译：

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V族过渡金属硫族硫化物单层中的巨谷分裂和谷极化等离子体。

二维VI族过渡金属二卤化物（TMD）提供了一个有前途的平台，用于在Valleytronics中编码和操纵量子信息。但是，这两个谷在能量上退化，受到时间反转对称性（TRS）的保护。为了消除这种退化，需要通过施加外部磁场或使用磁性稀土氧化物衬底破坏TRS。在这里，我们预测实现此目标的不同策略。我们认为，TRS本质上断裂的铁磁性V V TMD单层可以产生更大的谷值和自旋分裂。极化的ZnS（0001）表面也用作衬底，该衬底将波谷转移到低能态（接近费米能级）。此外，通过计算其集体的电子激发行为，我们证明了这样的系统拥有一个巨大的山谷极化太赫兹等离子体。我们的结果证明了设计和使用Valleytronic器件的新方法，这在根本上和技术上都很重要。