Graphene as a Tunable Nonradiative Bath for Moiré Excitons
Abstract
A minimal theory of nonradiative energy transfer from a two-dimensional (2D) moiré exciton to a nearby graphene layer is presented. From Fermi's golden rule the transfer rate is the overlap of the exciton near-field spectrum with the dissipative density response of graphene, weighted by an exciton form factor, and it reproduces the established GET∝ z−4 law in the point-dipole limit. A finite exciton size filters out the high-momentum near field once the spacer thickness approaches the transition-polarization radius RX, so the distance dependence of the rate---and of the photoluminescence (PL) quenching---probes the exciton size. A low-momentum expansion shows that, relative to the calibrated point-dipole response of the same bath, this leading correction is set by RX alone. In the ideal coherent-envelope limit the accompanying giant oscillator strength makes the rate non-monotonic in the exciton size, with a peak near lX≈ z. Treating graphene as a gate-tunable bath, Pauli blocking suppresses the interband channel once 2|muF| approaches ℏω, partially restoring PL, and a full random-phase-approximation benchmark confirms the normalized interband distance dependence to within a few percent away from the threshold. Mapping the PL observables across the transition-metal dichalcogenide/hexagonal boron nitride/graphene parameter space, we find that a graphene gate acts not as a passive electrostatic element but as a tunable 2D electronic reservoir probed through exciton PL quenching.
Versions
Related
- Momentum-selective graphene spectroscopy of moiré excitons
- Tensor-network methodology for real-space super-moiré excitons
- Room-temperature local strain control of moiré excitons in MoS2/WSe2 heterobilayers
- Hidden valley dynamics behind vanishing circular polarization in moiré excitons
- Single-atom billiards in an ultracold bath with energy-tunable collisions and threshold-sensitive detection
BibTeX
@misc{wakabayashi2026graphene,
title = {{Graphene as a Tunable Nonradiative Bath for Moiré Excitons}},
author = {Katsunori Wakabayashi},
howpublished = {arXiv},
year = {2026},
month = jul,
doi = {10.48550/arxiv.2606.28591},
eprint = {2606.28591},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2606.28591},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Graphene as a Tunable Nonradiative Bath for Moiré Excitons
AU - Katsunori Wakabayashi
PY - 2026
DA - 2026/07/31
PB - arXiv
DO - 10.48550/arxiv.2606.28591
UR - https://arxiv.org/abs/2606.28591
AB - A minimal theory of nonradiative energy transfer from a two-dimensional (2D) moiré exciton to a nearby graphene layer is presented. From Fermi's golden rule the transfer rate is the overlap of the exciton near-field spectrum with the dissipative density response of graphene, weighted by an exciton form factor, and it reproduces the established GET∝ z^−4 law in the point-dipole limit. A finite exciton size filters out the high-momentum near field once the spacer thickness approaches the transition-polarization radius R_X, so the distance dependence of the rate---and of the photoluminescence (PL) quenching---probes the exciton size. A low-momentum expansion shows that, relative to the calibrated point-dipole response of the same bath, this leading correction is set by R_X alone. In the ideal coherent-envelope limit the accompanying giant oscillator strength makes the rate non-monotonic in the exciton size, with a peak near lX≈ z. Treating graphene as a gate-tunable bath, Pauli blocking suppresses the interband channel once 2|muF| approaches ℏω, partially restoring PL, and a full random-phase-approximation benchmark confirms the normalized interband distance dependence to within a few percent away from the threshold. Mapping the PL observables across the transition-metal dichalcogenide/hexagonal boron nitride/graphene parameter space, we find that a graphene gate acts not as a passive electrostatic element but as a tunable 2D electronic reservoir probed through exciton PL quenching.
ER -