Bilayer WSe$_2$ as a natural platform for interlayer exciton condensates in the strong coupling limit
Abstract
Exciton condensates (EC) are macroscopic coherent states arising from condensation of electron-hole pairs. Bilayer heterostructures, consisting of two-dimensional electron and hole layers separated by a tunnel barrier, provide a versatile platform to realize and study EC. The tunnel barrier suppresses recombination yielding long-lived excitons. However, this separation also reduces interlayer Coulomb interactions, limiting the exciton binding strength. Here, we report the observation of EC in naturally occurring 2H-stacked bilayer WSe. In this system, the intrinsic spin-valley structure suppresses interlayer tunneling even when the separation is reduced to the atomic limit, providing access to a previously unattainable regime of strong interlayer coupling. Using capacitance spectroscopy, we investigate magneto-EC, formed when partially filled Landau levels (LL) couple between the layers. We find that the strong-coupling EC show dramatically different behaviour compared with previous reports, including an unanticipated variation of the EC robustness with the orbital number, and find evidence for a transition between two types of low-energy charged excitations. Our results provide a demonstration of tuning EC properties by varying the constituent single-particle wavefunctions.
Keywords
Cite
@article{arxiv.2108.10477,
title = {Bilayer WSe$_2$ as a natural platform for interlayer exciton condensates in the strong coupling limit},
author = {Qianhui Shi and En-Min Shih and Daniel Rhodes and Bumho Kim and Katayun Barmak and Kenji Watanabe and Takashi Taniguchi and Zlatko Papić and Dmitry A. Abanin and James Hone and Cory R. Dean},
journal= {arXiv preprint arXiv:2108.10477},
year = {2022}
}