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Dynamical Phase Transitions in the Photodriven Charge-Ordered Dirac-Electron System
Yasuhiro Tanaka1, Masahito Mochizuki1
1Department of Applied Physics, Waseda University, Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.
Physical Review Letters
|August 8, 2022
Summary
Irradiating organic salts with circularly polarized light drives photoinduced phase transitions. This research reveals transitions from charge-ordered insulators to Dirac semimetals and Chern insulators, governed by electron dynamics.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Mechanics
Background:
- Organic salts like α-(BEDT-TTF)2I3 exhibit complex electronic behaviors.
- Understanding photoinduced phase transitions is crucial for novel electronic devices.
Purpose of the Study:
- To theoretically investigate photoinduced phase transitions and charge dynamics.
- To explore the behavior of interacting Dirac electrons in a charge-ordered system.
Main Methods:
- Utilizing the extended Hubbard model for organic salt α-(BEDT-TTF)2I3.
- Employing numerical simulations based on the time-dependent Schrödinger equation.
- Applying Floquet theory to analyze driven quantum systems.
Main Results:
- Observed successive dynamical phase transitions under circularly polarized light.
- Identified transitions from charge-ordered insulator to Dirac semimetal, then to Chern insulator.
- Demonstrated light-induced closing of charge gap and opening of topological gap.
Conclusions:
- Photoinduced phase transitions are driven by charge dynamics of correlated Dirac electrons.
- Circularly polarized light plays a key role in melting charge order and breaking time-reversal symmetry.
- The study provides insights into controlling topological phases in quantum materials.
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