Anyons at impurities: Fractional charge measurement and "wrong sign" binding

Abstract

Recent photoluminescence experiments in twisted MoTe$_2$ have reported signatures of anyons binding to trapped trions. The measured binding energies near the fractional Chern insulators at fillings of $ν=-2/3$ and $-3/5$ have a ratio close to the fractional-charge ratio $5/3$, even though such scaling is not generally guaranteed for the expected short-range trion-anyon interaction. We model the trapped trion as a fixed impurity, and investigate anyon-impurity binding using a lowest-Landau-level model with exact diagonalization and Jain wavefunctions. Surprisingly, we find that the anyon-impurity binding energy ratio between $ν=-2/3$ and $-3/5$ is close to $5/3$ for either short- or long-ranged impurity-electron interactions. However, the ratio departs strongly from the charge ratio at intermediate ranges or different Jain states. Remarkably, we also uncover "wrong-sign" binding, whereby both quasiholes and quasiparticles can bind to either sign of a short-range impurity potential by selecting orbital channels with favorable local density oscillations. Our findings show that localized excitons or trions can be used to probe the internal density profile of anyons.