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arXiv · 2001.03812

Diffusivity Reveals Three Distinct Phases of Interlayer Excitons in MoSe2/WSe2 Heterobilayers

Jue Wang·Qianhui Shi·En-Min Shih·Lin Zhou·Wenjing Wu·Yusong Bai·Daniel A. Rhodes·Katayun Barmak·James Hone·Cory R. Dean·X. -Y. Zhu
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Abstract

Charge separated interlayer excitons in transition metal dichalcogenide (TMDC) heterobilayers are being explored for moir\'e 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 moir\'e-potential to the modestly mobile exciton gas as exciton density increases to ne/h ~ 1011 cm-2 and from the exciton gas to the highly mobile charge separated electron/hole plasma for ne/h > 1012 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.

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Jue Wang, Qianhui Shi, En-Min Shih, Lin Zhou, Wenjing Wu, Yusong Bai, Daniel A. Rhodes, Katayun Barmak, James Hone, Cory R. Dean, X. -Y. Zhu. 2020-01-11. Diffusivity Reveals Three Distinct Phases of Interlayer Excitons in MoSe2/WSe2 Heterobilayers. https://doi.org/10.1103/physrevlett.126.106804

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