Imaging the phase diagram of electron solids in Bernal bilayer graphene (part II)

In the interacting two-dimensional electron gas, a variety of electron solids can form with distinct lattice symmetries and composite particle numbers. Recently, a Wigner crystal (WC)—a triangular electron solid—has been directly observed in the Landau level (LL) of Bernal-stacked bilayer graphene (BLG) using scanning tunneling microscopy (STM) [1]. This observation inspires the exploration of different types of electron solids, as well as their microscopic understanding. Here, we report a rich phase diagram of electron solids at partial fillings of LLs with different orbital numbers N = 0, 1, 2. We find a plethora of WCs, including a hole-like WC near fully filled LLs. We will discuss the role of exchange interactions in the electron solids formed near the quantum Hall ferromagnets. The intra-unit cell structure of the electron solid is potentially enriched by its corresponding LL wavefunction.



[1] Tsui, YC., et al. Nature 628, 287–292 (2024).