Scientific Achievement

• Researchers in the Van der Waals Heterostructures program directly observed quantum oscillations and reentrant quantum phase transitions in an excitonic insulator

Significance and Impact

• First observation of exciton insulator quantum oscillation in van der Waals electron-hole bilayers

Research Details

• Measured quantum transport of dipolar excitonic insulators under out-of-plane magnetic field
• Observed quantum oscillations in both electrical resistance and Coulomb drag current in a magnetic field
• Observed reentrant quantum phase transitions between the excitonic insulator and bilayer quantum Hall insulator at high magnetic field

Publication Details

R. Qi, Q. Li, Z. Zhang, J. Nie, B. Zou, Z. Cui, H. Kim, C. Sanborn, S. Chen,  J. Xie, T.  Taniguchi, K. Watanabe, M.F. Crommie, A.H. MacDonald, F. Wang, Nature Materials (2025).

DOI:10.1038/s41563-025-02316-5

Work was performed at Lawrence Berkeley National Lab.