Two-Dimensional Moiré Polaronic Electron Crystals
Eric A. Arsenault, Yiliu Li, Birui Yang, Xi Wang, Heonjoon Park, Edoardo Mosconi, Enrico Ronca, Takashi Taniguchi, Kenji Watanabe, Daniel R. Gamelin, Andrew J. Millis, Cory R. Dean, Filippo De Angelis, Xiaodong Xu, Xiaoyang Zhu
Abstract
Two-dimensional moiré materials have emerged as the most versatile platform for realizing quantum phases of electrons. Here, we explore the stability origins of correlated states in WSe_{2}/WS_{2} moiré superlattices. We find that ultrafast electronic excitation leads to partial melting of the Mott states on timescales 5 times longer than predictions from the charge hopping integrals and that the melting rates are thermally activated, with activation energies of 18±3 and 13±2 meV for the one- and two-hole Mott states, respectively, suggesting significant electron-phonon coupling. A density functional theory calculation of the one-hole Mott state confirms polaron formation and yields a hole-polaron binding energy of 16 meV. These findings reveal a close interplay of electron-electron and electron-phonon interactions in stabilizing the polaronic Mott insulators at transition metal dichalcogenide moiré interfaces.