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Updated: Jul 7, 2026
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Fabricating van der Waals Heterostructures with Precise Rotational Alignment
Published on: July 5, 2019
Electrically Switchable Ultraslow Dispersionless Polaritons via Twist Engineering in van der Waals Heterostructures
Guolong Ma1, Lu Wen1, Yike Yang1
1College of Physics, Sichuan University, Chengdu, Sichuan 610064, China.
Nano Letters
|July 6, 2026
Summary
Researchers achieved ultraslow polaritons in van der Waals materials using twist engineering. This breakthrough enables programmable nanoscale slow light devices with unprecedented control over light propagation.
Area of Science:
- Condensed Matter Physics
- Nanophotonics
- Materials Science
Background:
- Polaritons in van der Waals materials offer nanoscale light control.
- Achieving ultraslow polaritons in the low-momentum regime (<10 μm⁻¹) has been a significant challenge, limiting applications.
Purpose of the Study:
- To report a novel mechanism for realizing dispersionless phonon polaritons in hyperbolic hetero-bicrystals.
- To demonstrate ultraslow polaritons in the technologically critical low-momentum regime.
Main Methods:
- Utilizing twist engineering in hyperbolic hetero-bicrystals.
- Demonstrating ultraslow polaritons with group velocities as low as 10⁻⁵c.
- Integrating a gated graphene layer for dynamic electrical switching.
Main Results:
- Achieved ultraslow polaritons with group velocity down to 10⁻⁵c in the low-momentum regime.
- Demonstrated a 100-fold improvement over previous reports in ultraslow polariton generation.
- Enabled dynamic electrical switching between ultraslow and fast polariton modes with 2 orders of magnitude tunability.
Conclusions:
- The developed twist engineering approach enables highly tunable polaritons across diverse material systems.
- This work opens new avenues for developing nanoscale programmable slow light devices.
- The findings overcome previous limitations in achieving ultraslow polaritons at low momenta.
