Gate tunable spatial accumulation of valley-spin in chemical vapor deposition grown 40°-twisted bilayer WS2
Gate tunable spatial accumulation of valley-spin in chemical vapor deposition grown 40°-twisted bilayer WS2
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DOI：
10.1088/1674-4926/44/1/012001
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发表时间：
2023-01
影响因子：
5.1
通讯作者：
Siwen Zhao;Gonglei Shao;Z. Han;Song Liu;Tongyao Zhang
中科院分区：
文献类型：
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作者：
Siwen Zhao;Gonglei Shao;Z. Han;Song Liu;Tongyao Zhang
新兴的二维材料，特别是过渡金属二硫属化物（TMD），已知表现出具有长谷寿命的谷自由度，这在谷电子器件的实现中具有很大的希望。特别是，在这些系统中，光谷相互作用引起了人们的注意，因为谷磁化的电生成可以很容易地实现-与传统电子自旋相比，磁电（ME）效应的路径相当不同。然而，到目前为止，用扭曲双层TMD构造的莫尔图案在其谷自旋极化方面仍然在很大程度上未被探索，即使对称性可能不同于AB堆叠双层TMD。在这里，我们研究了谷霍尔效应（VHE）在40°扭曲的化学气相沉积（CVD）生长的WS 2莫尔晶体管，使用光学克尔旋转测量在20 K。我们观察到一个明确的门可调的空间分布的谷载流子不平衡引起的VHE时，在系统中施加电流。
The emerging two-dimensional materials, particularly transition metal dichalcogenides (TMDs), are known to exhibit valley degree of freedom with long valley lifetime, which hold great promises in the implementation of valleytronic devices. Especially, light–valley interactions have attracted attentions in these systems, as the electrical generation of valley magnetization can be readily achieved — a rather different route toward magnetoelectric (ME) effect as compared to that from conventional electron spins. However, so far, the moiré patterns constructed with twisted bilayer TMDs remain largely unexplored in regard of their valley spin polarizations, even though the symmetry might be distinct from the AB stacked bilayer TMDs. Here, we study the valley Hall effect (VHE) in 40°-twisted chemical vapor deposition (CVD) grown WS2 moiré transistors, using optical Kerr rotation measurements at 20 K. We observe a clear gate tunable spatial distribution of the valley carrier imbalance induced by the VHE when a current is exerted in the system.