Visualizing the Impact of Quenched Disorder on 2D Electron Wigner Solids
Published in Nature, 2025
Recommended citation: Ge, Z., Smith, C., He, Z., Yang, Y., Li, Q., Kim, H.-L., Xiang, Z., Xiao, J., Zhou, W., Kahn, S., Hu, A., Erdi, M., Banerjee, R., Taniguchi, T., Watanabe, K., Tongay, S. A., Morales, M. A., Zhang, S., Wang, F., & Crommie, M. F., "Visualizing the Impact of Quenched Disorder on 2D Electron Wigner Solids, " Nature B 654, 902 (2026).
Electron Wigner solids (WSs)1-12 provide an ideal system for understanding the competing effects of electron-electron and electron-disorder interactions, a central unsolved problem in condensed matter physics. Progress in this topic has been limited by a lack of single-defect-resolved experimental measurements as well as accurate theoretical tools to enable realistic experiment/theory comparison. Here we overcome these limitations by combining atomically-resolved scanning tunneling microscopy (STM) with neural-quantum-state quantum Monte Carlo (NQS-QMC) simulation of disordered 2D electron WSs to discover new disorder-induced physical regimes of correlated electron behavior. STM was used to image the electron density (ne) dependent evolution of electron WSs in gate-tunable bilayer MoSe2 devices with varying long-range (nLR) and short-range (nSR) disorder densities. These images were compared to NQS-QMC simulations using realistic disorder maps extracted from experiment, thus allowing the roles of different disorder types to be disentangled. We identify two distinct physical regimes for disordered electron WSs that depend on nSR. For nSR≲ne the WS behavior is dominated by long-range disorder and features extensive mixed solid-liquid phases, a new type of local re-entrant melting/crystallization, and prominent Friedel oscillations. In contrast, when nSR≫ne these features are suppressed and a more robust amorphous WS phase emerges that persists to higher ne, highlighting the importance of short-range disorder in this regime. Our work establishes a powerful framework for studying disordered quantum solids via a combined experimental-theoretical approach.