Temperature dependent moire trapping of interlayer excitons in MoSe2-WSe2 heterostructures
Temperature dependent moire trapping of interlayer excitons in MoSe2-WSe2 heterostructures
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DOI：
10.1038/s41699-021-00248-7
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发表时间：
2021-07-21
影响因子：
9.7
通讯作者：
Schaibley, John R.
中科院分区：
文献类型：
--
作者：
Mahdikhanysarvejahany, Fateme;Shanks, Daniel N.;Schaibley, John R.
MoSe 2-WSe 2异质结构具有强束缚的层间激子（IX），当扭转角接近0度或60度时，其表现出明亮的光致发光（PL）。在过去的几年里，已经有许多关于这些异质结构的光学响应的报道，但没有统一的模型来理解IX的动力学及其温度依赖性。在这里，我们进行了全面的研究的温度，激发功率，和随时间变化的PL的IX。我们观察到一个显着的降低PL强度以上的转变温度，我们归因于从本地化到离域IX的过渡。令人惊讶的是，我们发现了一个简单的反关系的IX PL能量和转变温度，表现出相反的功率依赖行为，近0度和60度的样品。我们的结论是，这种温度依赖性是IX-IX交换相互作用的结果，其效果被抑制的云纹势捕获IX在低温下。
MoSe2-WSe2 heterostructures host strongly bound interlayer excitons (IXs), which exhibit bright photoluminescence (PL) when the twist angle is near 0 degrees or 60 degrees. Over the past several years, there have been numerous reports on the optical response of these heterostructures but no unifying model to understand the dynamics of IXs and their temperature dependence. Here we perform a comprehensive study of the temperature, excitation power, and time-dependent PL of IXs. We observe a significant decrease in PL intensity above a transition temperature that we attribute to a transition from localized to delocalized IXs. Astoundingly, we find a simple inverse relationship between the IX PL energy and the transition temperature, which exhibits opposite power-dependent behaviors for near 0 degrees and 60 degrees samples. We conclude that this temperature dependence is a result of IX-IX exchange interactions, whose effect is suppressed by the moire potential trapping IXs at low temperature.