Imaging quantum melting in a disordered 2D Wigner solid
- Ziyu Xiang
- Hongyuan Li
- Jianghan Xiao
- Mit H. Naik
- Zhehao Ge
- Zehao He
- Sudi Chen
- Jiahui Nie
- Shiyu Li
- Yifan Jiang
- Renee Sailus
- Rounak Banerjee
- Takashi Taniguchi
- Kenji Watanabe
- Sefaattin Tongay
- Steven G. Louie
- Michael F. Crommie
- Feng Wang
2025-05-22
Two-dimensional strongly interacting electrons crystalize into a solid phase known as the Wigner crystal at low densities and form a Fermi liquid at high densities. At intermediate densities, the two-dimensional solid evolves into a strongly correlated liquid phase around a critical density. We observed this quantum melting of a disordered Wigner solid in bilayer molybdenum diselenide (MoSe 2 ) using a noninvasive scanning tunneling microscopy imaging technique. At low densities, the Wigner solid forms nanocrystalline domains pinned by local disorder. It exhibits a quantum densification behavior with increased densities in the solid phase. Above a threshold density, the Wigner solid melts locally and enters a mixed phase in which solid and liquid regions coexist. The liquid regions expand and form a percolation network at even higher densities.