Related Experiment Video
Updated: Jul 15, 2026
08:38
Electrospray Deposition of Uniform Thickness Ge23Sb7S70 and As40S60 Chalcogenide Glass Films
Published on: August 19, 2016
Ultrafast laser-induced phase transitions in amorphous GeSb films
J P Callan1, A M Kim, C A Roeser
1Department of Physics and Division of Engineering and Applied Sciences, Gordon McKay Laboratory, Harvard University, 9 Oxford Street, Cambridge, Massachusetts 02138, USA. paul_callan@post.harvard.edu
Physical Review Letters
|May 1, 2001
Summary
Femtosecond laser pulses induce ultrafast phase transitions in amorphous germanium-antimony (GeSb) films. Contrary to disorder-to-order models, the transition leads to a distinct nonthermal, disordered state, not a crystalline phase.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Ultrafast Spectroscopy
Background:
- Amorphous semiconductors are crucial for optical data storage.
- Understanding ultrafast phase transitions in these materials is key to improving device performance.
- Previous models suggested laser-induced transitions were disorder-to-order.
Purpose of the Study:
- To investigate the dynamics of laser-induced phase transitions in Sb-rich amorphous GeSb films.
- To clarify the nature of the transient phase formed after femtosecond laser excitation.
- To challenge existing disorder-to-order transition models.
Main Methods:
- Time-resolved spectral dielectric function measurements.
- Femtosecond laser pulse excitation of Sb-rich amorphous GeSb films.
- Analysis of the dielectric response to probe phase changes.
Main Results:
- Ultrafast nonthermal phase generation within 200 fs.
- The transient phase's dielectric function differs significantly from the crystalline state.
- Observed dielectric properties align with a liquid-like disordered state, not a crystalline phase.
Conclusions:
- Laser-induced phase transition in amorphous GeSb is not a simple disorder-to-order process.
- A novel, distinct disordered state is formed rapidly after excitation.
- These findings necessitate a revision of phase transition mechanisms in amorphous chalcogenides.
