Remarkably Deep Moire Potential for Intralayer Excitons in MoSe2/MoS2 Twisted Heterobilayers
Remarkably Deep Moire Potential for Intralayer Excitons in MoSe2/MoS2 Twisted Heterobilayers
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DOI：
10.1021/acs.nanolett.2c04524
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发表时间：
2023-02-06
期刊：
影响因子：
10.8
通讯作者：
Chang, Wen-Hao
中科院分区：
文献类型：
--
作者：
Lin, Bo-Han;Chao, Yung-Chun;Chang, Wen-Hao
在扭曲的货车德瓦尔斯双层膜中形成的莫尔超晶格已经成为在二维材料中产生新的电子态的新的调谐旋钮。激子特性也可以由于莫尔电位的存在而急剧改变。然而，量化激子的莫尔势是不平凡的。通过创建一个大的合奏的MoSe 2/MoS 2异质双层的扭转角的系统变化，我们映射出的层间和层内激子的迷你带作为扭转角的函数，从中我们确定激子的莫尔电位。令人惊讶的是，层内激子的莫尔电位深度高达类似于130毫电子伏，相当于层间激子。这一结果与基于密度泛函理论的理论计算明显不同，该理论计算表明层内激子的莫尔势小一个数量级。在莫尔晶胞内的结构重建的框架内理解非常深的层内莫尔电位。
A moire superlattice formed in twisted van der Waals bilayers has emerged as a new tuning knob for creating new electronic states in two-dimensional materials. Excitonic properties can also be altered drastically due to the presence of moire potential. However, quantifying the moire potential for excitons is nontrivial. By creating a large ensemble of MoSe2/MoS2 heterobilayers with a systematic variation of twist angles, we map out the minibands of interlayer and intralayer excitons as a function of twist angles, from which we determine the moire potential for excitons. Surprisingly, the moire potential depth for intralayer excitons is up to similar to 130 meV, comparable to that for interlayer excitons. This result is markedly different from theoretical calculations based on density functional theory, which show an order of magnitude smaller moire potential for intralayer excitons. The remarkably deep intralayer moire potential is understood within the framework of structural reconstruction within the moire unit cell.