1. Bilayer WSe2 as a natural platform for interlayer exciton condensates in the strong coupling limit
- Author
-
Qianhui Shi, En-Min Shih, Daniel Rhodes, Bumho Kim, Katayun Barmak, Kenji Watanabe, Takashi Taniguchi, Zlatko Papić, Dmitry A. Abanin, James Hone, and Cory R. Dean
- Subjects
Condensed Matter - Mesoscale and Nanoscale Physics ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,Biomedical Engineering ,FOS: Physical sciences ,General Materials Science ,Bioengineering ,Electrical and Electronic Engineering ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics - Abstract
Exciton condensates (ECs) are macroscopic coherent states arising from condensation of electron–hole pairs1. Bilayer heterostructures, consisting of two-dimensional electron and hole layers separated by a tunnel barrier, provide a versatile platform to realize and study ECs2,3,4. The tunnel barrier suppresses recombination, yielding long-lived excitons5,6,7,8,9,10. However, this separation also reduces interlayer Coulomb interactions, limiting the exciton binding strength. Here, we report the observation of ECs in naturally occurring 2H-stacked bilayer WSe2. In this system, the intrinsic spin–valley structure suppresses interlayer tunnelling 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-ECs, formed when partially filled Landau levels couple between the layers. We find that the strong-coupling ECs show dramatically different behaviour compared with previous reports, including an unanticipated variation of 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.
- Published
- 2022