Photoinduced twist and untwist of moiré superlattices
Article meta
Article Date: 12 November 2025
Article URL: https://www.nature.com/articles/s41586-025-09707-3
Article Title: Photoinduced twist and untwist of moiré superlattices
Article Image: (none provided)
Summary
This Nature paper reports direct, time-resolved observations of light-driven twisting and untwisting in moiré superlattices formed by WSe2/MoSe2 heterobilayers. Using high-magnification ultrafast electron diffraction (UED), complemented by time- and angle-resolved photoemission (trARPES) and detailed modelling, the team tracks oscillatory changes in moiré satellite diffraction consistent with a torsional (vortex-like) lattice displacement. They fit a dynamical model to the UED data and identify a dominant oscillatory component centred around ~510 ± 90 GHz, with different signatures depending on initial twist angle (examples shown for ~2° and ~57° samples). Simulations and DFT calculations link the observed lattice motion to changes in electronic bands and deformation potentials. Data points and CSV source data are provided with the paper and simulation inputs are available on GitHub.
Key Points
- The team used ultrafast electron diffraction to capture photoinduced changes in moiré satellite diffraction in WSe2/MoSe2 heterobilayers.
- They observe an oscillatory twisting/untwisting motion (torsional lattice displacement) with a central frequency ~510 ± 90 GHz in their dynamical model.
- Signatures differ with initial twist angle: small-angle (≈2°) and large-angle (≈57°) heterobilayers show distinct transient diffraction responses and spectral features.
- trARPES measurements provide complementary carrier dynamics (sub-ps to 100s ps timescales) that help connect electronic excitation to lattice motion.
- DFT and phonon-modelling link twist and interlayer spacing changes to band-structure shifts via deformation potentials, implying optical control can tune moiré electronic landscapes.
- All primary experimental data are provided (figures and CSV source data) and simulation input files are shared on GitHub: https://github.com/imaitygit/PaperData/tree/main/PhotoinducedTwist.
Context and relevance
Moiré superlattices in twisted 2D materials are a hotbed for correlated physics (Mott states, superconductivity, moiré excitons). This work adds a new axis: ultrafast, optical control of the moiré geometry itself. Demonstrating that light can drive a coherent torsional mode that changes the local twist angle — and that this couples to electronic structure — suggests routes to dynamically tune moiré potentials on sub-picosecond timescales. That matters for anyone working on moiré engineering, ultrafast control of quantum phases, and exciton/phonon-mediated phenomena in 2D heterostructures.
Author’s take
Punchy: this is a neat, technical demonstration that you can make a moiré lattice ‘twist’ with light and watch it unwind. If you care about controlling correlated states or optically tuning band topology in 2D stacks, the detailed methods and dynamical modelling here are worth a close read — the supplemental material and shared code make replication and follow-up practical.
Why should I read this?
Short version: they show you can nudge a moiré lattice with light and watch it oscillate — fast. If you’re after ways to switch or tune moiré-driven electronic phases, or to manipulate excitons/phonons on ultrafast timescales, this paper gives concrete experimental evidence, a dynamical model, and the data/code to dig deeper. We saved you time by reading it: the takeaways and resources are laid out so you can jump straight to the figures, CSV data and GitHub inputs.