Modeling thermoreflectance in Au and Ni from molecular dynamics

Area of Science:

• Materials Science
• Computational Physics
• Condensed Matter Physics

Background:

• Thermoreflectance measurements probe electron-phonon coupling in metals.
• Molecular dynamics (MD) simulations typically exclude electron-phonon coupling.
• This limits MD's ability to model thermoreflectance, electric conductivity, and thermal transport.

Purpose of the Study:

• To extend MD simulations to include electron-phonon coupling.
• To model thermoreflectance experiments using a modified MD approach.
• To validate the extended MD method against experimental data.

Main Methods:

• Utilized the Finnis, Agnew, and Foreman (FAF) method, originally for electronic stopping power.
• Applied the FAF method within MD simulations to account for electron-phonon interactions.
• Performed simulations for gold (Au) and nickel (Ni) under pulsed-laser irradiation conditions.

Main Results:

• Successfully reproduced experimental thermoreflectance data at room temperature for Au and Ni.
• Demonstrated the transferability of the FAF-extended MD method across different metals.
• Enabled discussion and selection of appropriate theories for electron-phonon coupling amplitude within the FAF framework.

Conclusions:

• The FAF method can be effectively adapted to incorporate electron-phonon coupling into MD simulations.
• This approach opens possibilities for more accurate modeling of thermoreflectance and related phenomena.
• The work paves the way for reintroducing electric conductivity into MD simulations for metals.