Diffusivity Reveals Three Distinct Phases of Interlayer Excitons in MoSe2/WSe2 Heterobilayers
Diffusivity Reveals Three Distinct Phases of Interlayer Excitons in MoSe2/WSe2 Heterobilayers
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DOI：
10.1103/physrevlett.126.106804
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发表时间：
2021-03-11
影响因子：
8.6
通讯作者：
Zhu, X-Y
中科院分区：
文献类型：
--
作者：
Wang, Jue;Shi, Qianhui;Zhu, X-Y
电荷分离的层间激子在过渡金属二硫族化物异质双层膜中的莫尔激子晶格和激子凝聚体中被探索。永久偶极矩的存在和弱屏蔽库仑相互作用使得多体相互作用对于层间激子特别强。在这里，我们使用时间和空间分辨的光致发光成像揭示了MoSe 2/WSe 2异质双层中层间激子的两个不同的相变：当激子密度增加到类似于10（11）cm（-2）的n（ex）时，从莫尔势中捕获的激子到适度移动的激子气体，以及当n（ex）> 10（12）时，从激子气体到高度移动的电荷分离的电子-空穴等离子体cm（-2）。后者是莫特转变，并在光电导测量中得到证实。这些发现为实现层间激子的量子态设置了基本限制。
Charge separated interlayer excitons in transition metal dichalcogenide heterobilayers are being explored for moire exciton lattices and exciton condensates. The presence of permanent dipole moments and the poorly screened Coulomb interaction make many-body interactions particularly strong for interlayer excitons. Here we reveal two distinct phase transitions for interlayer excitons in the MoSe2/WSe2 heterobilayer using time and spatially resolved photoluminescence imaging: from trapped excitons in the moire potential to the modestly mobile exciton gas as exciton density increases to n(ex) similar to 10(11) cm(-2) and from the exciton gas to the highly mobile charge separated electron-hole plasma for n(ex) > 10(12) cm(-2). The latter is the Mott transition and is confirmed in photoconductivity measurements. These findings set fundamental limits for achieving quantum states of interlayer excitons.