2025/05/11 by Junghwan Kim, Kim, Junghwan, Hanan Dery +3 · 2 citations
Chemistry · Physics and Astronomy · #Advanced Physical and Chemical Molecular Interactions #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Quantum and electron transport phenomena #Strong Light-Matter Interactions #Strongly Correlated Electrons (cond-mat.str-el)
paper · pdf · doi:10.48550/arxiv.2505.06984
openalex publication_date 2025/05/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Long-range Coulomb forces give rise to correlated insulating states when charge particles populate a moiré superlattice at certain fractional filling factors. Such behavior is characterized by a broken translation symmetry wherein particles spontaneously form a Wigner crystal. Focusing on the experimental findings of Xu et al. [Nature 587, 214 (2020)], we present a theory that captures the correlated insulating state of a fractionally-filled moiré superlattice through the energy shift and change in oscillator strength of the exciton absorption resonance. The theory shows that the experimental findings can only be supported if the electrons reside in a charge-ordered state (i.e., electrons are not randomly distributed among the sites of the moiré superlattice). Furthermore, we explain why the energy shifts of exciton resonances are qualitatively different in cases that the superlattice is nearly empty compared with a superlattice whose sites are doubly occupied.