Direct calculation of light-induced structural change and diffusive motion in glassy As2Se3

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Chemistry

Background:

• Glassy arsenic triselenide (As2Se3) exhibits complex photostructural changes.
• Understanding these changes is crucial for optoelectronic applications.

Purpose of the Study:

• To simulate and elucidate the photostructural dynamics of As2Se3.
• To investigate the mechanisms behind light-induced transformations in amorphous chalcogenides.

Main Methods:

• First-principles molecular dynamics simulations.
• Modeling excited electronic dynamics.
• Analysis of bond breaking/switching and defect rearrangement.

Main Results:

• Simulations revealed local bond breaking and switching at short illumination times.
• Long-time relaxation showed defect pair rearrangement and polaronlike oscillations.
• Observed diffusive motion suggests initial athermal photomelting.

Conclusions:

• The study provides a detailed, atomistic view of As2Se3 photostructural evolution.
• Identified mechanisms include electronic excitation, defect dynamics, and collective oscillations.
• Findings offer insights into light-induced phase transitions in amorphous materials.