Ultrafast and persistent photoinduced phase transition at room temperature monitored by streaming powder diffraction

Area of Science:

• Materials Science
• Condensed Matter Physics
• Physical Chemistry

Background:

• Ultrafast photoinduced phase transitions offer novel routes for controlling material properties.
• Understanding the dynamics of these transitions is crucial for developing advanced materials.
• Room temperature transitions with persistent effects are of significant interest.

Purpose of the Study:

• To investigate the photoinduced phase transformation in Rb0.94Mn0.94Co0.06[Fe(CN)6]0.98.
• To elucidate the structural and symmetry changes during the transition.
• To explore the potential of a novel powder streaming technique for studying ultrafast dynamics.

Main Methods:

• Utilized ultrafast X-ray diffraction to monitor structural changes.
• Developed a specialized powder sample streaming technique.
• Applied Landau theory to rationalize the observed phase transition dynamics.

Main Results:

• Photoinduced polarons were observed to expand the lattice.
• The tetragonal-to-cubic phase transition occurred within 100 picoseconds above a threshold fluence.
• The transition was characterized as an elastically-driven and cooperative process.

Conclusions:

• The study demonstrates the feasibility of inducing and controlling phase transitions with light.
• The developed powder streaming technique is effective for studying ultrafast and non-reversible dynamics.
• Findings provide fundamental insights into far-from-equilibrium electronic and structural dynamics in materials.