Laser-pump/X-ray-probe experiments with electrons ejected from a Cu(111) target: space-charge acceleration.

Area of Science:

• Surface science
• Atomic physics
• Laser-matter interactions

Background:

• Understanding electron emission is crucial for surface analysis and material science.
• Laser excitation can significantly alter the electronic properties of materials.

Purpose of the Study:

• To investigate electron emission characteristics from Cu(111) under combined X-ray and laser excitation.
• To analyze the impact of high target excitation on photo and Auger electron properties.
• To understand space-charge effects on electron energy spectra.

Main Methods:

• Utilized grazing-incidence X-ray excitation on an atomically clean Cu(111) sample.
• Employed intense infrared laser irradiation at the BESSY II slicing facility.
• Conducted time-resolved pump-and-probe measurements to study electron properties.

Main Results:

• Observed strong electron energy shifts in the emitted electrons.
• Attributed these shifts to space-charge acceleration effects.
• Investigated the dependence of energy shifts on laser power and electron energy.

Conclusions:

• Space-charge acceleration significantly influences electron emission spectra under intense laser excitation.
• Experimental findings are supported by new theoretical models.
• Provides insights into laser-induced electron dynamics in metals.