Evidence of high-temperature exciton condensation in 2D atomic double layers
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.
Keywords
Cite
@article{arxiv.2103.16407,
title = {Evidence of high-temperature exciton condensation in 2D atomic double layers},
author = {Zefang Wang and Daniel A. Rhodes and Kenji Watanabe and Takashi Taniguchi and James C. Hone and Jie Shan and Kin Fai Mak},
journal= {arXiv preprint arXiv:2103.16407},
year = {2021}
}