Thermodynamic behavior of correlated electron-hole fluids in van der Waals heterostructures

• DOI: 10.1038/s41467-023-43799-7
• Publication Date: 2023-12-13T06:01:42Z
• Authors: Ruishi Qi; Andrew Y. Joe; Zuocheng Zhang; Yongxin Zeng; Tiancheng Zheng; Qixin Feng; Jingxu Xie; Emma Regan; Zheyu Lu; Takashi Taniguchi; Kenji Watanabe; Sefaattin Tongay; Michael F. Crommie; Allan H. MacDonald; Feng Wang
• Keywords: Electron hole; Electronic correlation

Coupled two-dimensional electron-hole bilayers provide a unique platform to study strongly correlated Bose-Fermi mixtures in condensed matter. Electrons and holes spatially separated layers can bind form interlayer excitons, composite Bosons expected support high-temperature exciton condensates. The excitons also interact with excess charge carriers when electron hole densities are unequal. Here, we use optical spectroscopy quantitatively probe the local thermodynamic properties of fluids MoSe2/hBN/WSe2 heterostructures. We observe discontinuity chemical potentials at matched densities, definitive signature an excitonic insulator ground state. is stable up Mott density ~0.8 × 1012 cm-2 has thermal ionization temperature ~70 K. dependence electron, hole, reveals strong correlation effects across phase diagram. Compared non-interacting uniform distribution, lead significant attractive exciton-exciton exciton-charge interactions fluid. Our work highlights quantum behavior that emerge systems.