Interlayer Trions in the MoS2/WS2 van der Waals Heterostructure
Interlayer Trions in the MoS2/WS2 van der Waals Heterostructure
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DOI：
10.1021/acs.nanolett.7b05224
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发表时间：
2018-02-01
期刊：
影响因子：
10.8
通讯作者：
Thygesen, Kristian Sommer
中科院分区：
文献类型：
--
作者：
Deilmann, Thorsten;Thygesen, Kristian Sommer
货车德瓦耳斯异质结构中的电子激发可以具有层间或层内特征，这取决于所涉及的电荷（电子和空穴）的空间定位。在中性电子空穴对（激子）的情况下，这两种类型的激发已经在理论和实验上进行了探索。相比之下，带电三离子的研究迄今为止仅限于层内类型。在这里，我们调查了完整的一套层间激发MoS 2/WS 2异质结使用一种新的从头算方法，它允许一个一致的治疗激子和trions在相同的理论基础。我们的计算预测存在的束缚层间激子下面的中性层间激子。我们得到的结合能为18/28毫电子伏的正/负层间trions与两个电子/空穴位于同一层。与此相反，一个可以忽略不计的结合能被发现的trions具有两个相同的带电粒子在不同的层。我们的结果推进了对掺杂货车德瓦耳斯异质结构中电子激发及其对光学性质影响的理解。
Electronic excitations in van der Waals heterostructures can have interlayer or intralayer character depending on the spatial localization of the involved charges (electrons and holes). In the case of neutral electron-hole pairs (excitons), both types of excitations have been explored theoretically and experimentally. In contrast, studies of charged trions have so far been limited to the intralayer type. Here we investigate the complete set of interlayer excitations in a MoS2/WS2 heterostructure using a novel ab initio method, which allows for a consistent treatment of both excitons and trions at the same theoretical footing. Our calculations predict the existence of bound interlayer trions below the neutral interlayer excitons. We obtain binding energies of 18/28 meV for the positive/negative interlayer trions with both electrons/holes located on the same layer. In contrast, a negligible binding energy is found for trions which have the two equally charged particles on different layers. Our results advance the understanding of electronic excitations in doped van der Waals heterostructures and their effect on the optical properties.