Laser-Induced Cooperative Transition in Molecular Electronic Crystal

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Information Science

Background:

• Strongly correlated materials exhibit complex electronic and magnetic states.
• Controlling non-equilibrium phase transitions is crucial for quantum technologies.
• Stabilizing transient states in molecular electronic solids remains challenging.

Purpose of the Study:

• To demonstrate dynamic control and stabilization of cooperative phases in molecular electronic solids.
• To investigate the charge-spin bistability in potassium-7,7,8,8-tetracyanoquinodimethane (K-TCNQ).
• To explore the potential of pulsed electromagnetic excitation for creating novel electro-magnetic phases.

Main Methods:

• Utilized 8 ns pulsed laser excitation (532 nm) to induce lattice perturbation in K-TCNQ.
• Performed noise spectroscopy, in situ high-pressure measurements, and electron spin resonance (ESR).
• Employed theoretical modeling and scanning tunneling microscopy/spectroscopy (STM/STS) for comprehensive analysis.

Main Results:

• Achieved a stable, long-lived (over 400 days) conducting paramagnetic state (≈42 Ωcm).
• Demonstrated charge-spin bistability across a wide temperature range (2–360 K).
• Confirmed the cooperative nature of the transition, requiring charge-spin-lattice decoupling.

Conclusions:

• Pulsed excitation offers collective control for generating and stabilizing strongly correlated electronic and magnetic orders.
• Ultrahigh-strain-rate excitation is key to activating and stabilizing non-equilibrium phases.
• This work presents unique electro-magnetic phases with significant technological promise for quantum sensing and information technology.