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arXiv · 2103.16407

Evidence of high-temperature exciton condensation in 2D atomic double layers

Zefang Wang·Daniel A. Rhodes·Kenji Watanabe·Takashi Taniguchi·James C. Hone·Jie Shan·Kin Fai Mak
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Abstract

A Bose-Einstein condensate is the ground state of a dilute gas of bosons, such as atoms cooled to temperatures close to absolute zero. With much smaller mass, excitons (bound electron-hole pairs) are expected to condense at significantly higher temperatures. Here we study electrically generated interlayer excitons in MoSe2/WSe2 atomic double layers with density up to 10^12 cm-2. The interlayer tunneling current depends only on exciton density, indicative of correlated electron-hole pair tunneling. Strong electroluminescence (EL) arises when a hole tunnels from WSe2 to recombine with electron in MoSe2. We observe a critical threshold dependence of the EL intensity on exciton density, accompanied by a super-Poissonian photon statistics near threshold, and a large EL enhancement peaked narrowly at equal electron-hole densities. The phenomenon persists above 100 K, which is consistent with the predicted critical condensation temperature. Our study provides compelling evidence for interlayer exciton condensation in two-dimensional atomic double layers and opens up exciting opportunities for exploring condensate-based optoelectronics and exciton-mediated high-temperature superconductivity.

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Zefang Wang, Daniel A. Rhodes, Kenji Watanabe, Takashi Taniguchi, James C. Hone, Jie Shan, Kin Fai Mak. 2021-03-29. Evidence of high-temperature exciton condensation in 2D atomic double layers. https://doi.org/10.1038/s41586-019-1591-7

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