Ultrafast bond softening in bismuth: mapping a solid's interatomic potential with X-rays

Area of Science:

• Condensed matter physics
• Materials science
• Ultrafast science

Background:

• Intense femtosecond laser excitation creates unique, transient states of matter.
• High excitation densities significantly alter interatomic forces in solids.

Purpose of the Study:

• To map the carrier density-dependent interatomic potential of bismuth.
• To investigate bismuth as it approaches a solid-solid phase transition.

Main Methods:

• Utilized stroboscopic techniques with a high-brightness linear electron accelerator-based X-ray source.
• Employed pulse-by-pulse timing reconstruction for femtosecond resolution.
• Achieved quantitative characterization of the interatomic potential energy surface.

Main Results:

• Detailed mapping of the interatomic potential of bismuth was achieved.
• The study focused on the behavior of bismuth under high excitation densities.
• The research explored the transition towards a solid-solid phase change.

Conclusions:

• Femtosecond laser excitation provides a method to study inaccessible states of matter.
• Quantitative characterization of the interatomic potential energy surface is possible.
• The interatomic potential of highly excited solids can be precisely determined.