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Updated: Jan 15, 2026
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Fabricating van der Waals Heterostructures with Precise Rotational Alignment
Published on: July 5, 2019
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Optically Controlled Phase Transitions in 2D Se Allotropes
Pingwei Liu1, Dan Liu1,2, Kang Li1
1School of Physics, Southeast University, Nanjing, 211189, PR China.
The Journal of Physical Chemistry Letters
|October 15, 2025
Summary
Optically controlled phase transitions in 2D ferroelectric selenium (α-Se) enable precise data storage. Laser pulses activate specific phonon modes, inducing polarization reversal and forming a new 2D selenium allotrope (r-Se).
Area of Science:
- Condensed Matter Physics
- Materials Science
- Computational Chemistry
Background:
- Optically controlled phase transitions in materials offer advantages for data storage due to high response speed and nonvolatility.
- Two-dimensional (2D) ferroelectric materials are actively researched for advanced electronic applications.
Purpose of the Study:
- To demonstrate the precise manipulation of phase transitions in 2D ferroelectric α-Se using laser pulses.
- To investigate the underlying mechanisms of optically induced phase transitions and material transformation.
Main Methods:
- Real-time time-dependent density functional theory (rt-TDDFT) simulations.
- Analysis of coherent phonon mode activation and momentum scattering.
- Investigation of nonequilibrium atomic dynamics.
Main Results:
- Laser pulse application precisely controls phase transitions in 2D ferroelectric α-Se.
- Optical activation of specific phonon modes (A-1, A-2 at Γ-point) induces polarization reversal.
- Coherent evolution of phonon modes leads to the formation of a novel 2D selenium allotrope, denoted as r-Se.
Conclusions:
- Optically triggered coherent phonon dynamics provide a pathway for manipulating ferroelectric polarization.
- This research reveals a new method for creating novel 2D materials with potential data storage applications.
- The discovery of r-Se expands the family of 2D selenium allotropes and their potential functionalities.
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