Ultrafast Moiré Exciton Dynamics Revealed by Two-Dimensional Coherent Spectroscopy
Abstract
Moiré superlattices of van der Waals heterostructures confine excitons into discrete energy levels in finite-sized samples, yet their internal relaxation pathways remain obscured by inhomogeneous broadening. Here, using two-dimensional coherent spectroscopy (2DCS), we directly resolve seven discrete energy levels of the moiré-confined intralayer WS2 A exciton in an hBN-encapsulated WS2/WSe2 heterostructure, corresponding to a confinement depth of 57.02 meV. By tracking the population of these levels over picosecond delays, we uncover a two-stage thermalization process: an effective exciton temperature drops from 171.8 to 99.3 K within 1.2 ps through rapid intra-manifold population redistribution, followed by a slower recovery toward quasi-equilibrium mediated by exciton--environment interactions. Kullback--Leibler divergence analysis confirms the progressive transition from a non-equilibrium to a Boltzmann-distributed population. Our results establish state-resolved access to moiré exciton dynamics and provide a foundation for exploring nonequilibrium many-body phenomena in moiré quantum materials.
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BibTeX
@misc{zhang2026ultrafast,
title = {{Ultrafast Moiré Exciton Dynamics Revealed by Two-Dimensional Coherent Spectroscopy}},
author = {Deran Zhang and Zhexue Chen and Dongxue Chen and Tengfei Yan and Jianhua Jiang and Hui Dong},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.07539},
eprint = {2611.07539},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.07539},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Ultrafast Moiré Exciton Dynamics Revealed by Two-Dimensional Coherent Spectroscopy
AU - Deran Zhang
AU - Zhexue Chen
AU - Dongxue Chen
AU - Tengfei Yan
AU - Jianhua Jiang
AU - Hui Dong
PY - 2026
DA - 2026/11/05
PB - arXiv
DO - 10.48550/arxiv.2611.07539
UR - https://arxiv.org/abs/2611.07539
AB - Moiré superlattices of van der Waals heterostructures confine excitons into discrete energy levels in finite-sized samples, yet their internal relaxation pathways remain obscured by inhomogeneous broadening. Here, using two-dimensional coherent spectroscopy (2DCS), we directly resolve seven discrete energy levels of the moiré-confined intralayer WS_2 A exciton in an hBN-encapsulated WS_2/WSe_2 heterostructure, corresponding to a confinement depth of 57.02 meV. By tracking the population of these levels over picosecond delays, we uncover a two-stage thermalization process: an effective exciton temperature drops from 171.8 to 99.3 K within 1.2 ps through rapid intra-manifold population redistribution, followed by a slower recovery toward quasi-equilibrium mediated by exciton--environment interactions. Kullback--Leibler divergence analysis confirms the progressive transition from a non-equilibrium to a Boltzmann-distributed population. Our results establish state-resolved access to moiré exciton dynamics and provide a foundation for exploring nonequilibrium many-body phenomena in moiré quantum materials.
ER -