Evidence for moire excitons in van der Waals heterostructures
Evidence for moire excitons in van der Waals heterostructures
复制标题
DOI：
10.1038/s41586-019-0975-z
复制
发表时间：
2019-03-07
期刊：
影响因子：
64.8
通讯作者：
Li, Xiaoqin
中科院分区：
文献类型：
--
作者：
Kha Tran;Moody, Galan;Li, Xiaoqin
货车德瓦尔斯材料单层的隔离和堆叠的最新进展为最终二维极限中的量子材料的制备提供了方法（1，2）。在通过堆叠两个单层半导体形成的货车范德华异质结构中，晶格失配或旋转未对准引入了面内莫尔超晶格（3）。人们普遍认为，莫尔超晶格可以调制材料的电子能带结构，并导致传输特性，如非常规超导性（4）和相关性驱动的绝缘行为（5-7）;然而，莫尔超晶格对光学特性的影响尚未进行实验研究。在这里，我们报告的多个层间激子共振的观察，无论是积极或消极的圆极化发射在钼二硒/钨二硒（MoSe 2/WSe 2）异质双层小扭转角。我们将这些共振归因于限制在莫尔势内的激子基态和激发态。这种解释是支持复合动力学和依赖于这些层间激子共振扭转角和温度。这些结果表明，工程的可行性人工激子晶体使用货车德瓦尔斯异质结构的纳米光子学和量子信息的应用。
Recent advances in the isolation and stacking of monolayers of van der Waals materials have provided approaches for the preparation of quantum materials in the ultimate two-dimensional limit(1,2). In van der Waals heterostructures formed by stacking two monolayer semiconductors, lattice mismatch or rotational misalignment introduces an in-plane moire superlattice(3). It is widely recognized that the moire superlattice can modulate the electronic band structure of the material and lead to transport properties such as unconventional superconductivity(4) and insulating behaviour driven by correlations(5-7); however, the influence of the moire superlattice on optical properties has not been investigated experimentally. Here we report the observation of multiple interlayer exciton resonances with either positive or negative circularly polarized emission in a molybdenum diselenide/tungsten diselenide (MoSe2/WSe2) heterobilayer with a small twist angle. We attribute these resonances to excitonic ground and excited states confined within the moire potential. This interpretation is supported by recombination dynamics and by the dependence of these interlayer exciton resonances on twist angle and temperature. These results suggest the feasibility of engineering artificial excitonic crystals using van der Waals heterostructures for nanophotonics and quantum information applications.