Backscattering of Li+ ions from MoS2: Probing charge transfer through experiment and theory

Area of Science:

• Surface Science
• Atomic and Molecular Physics
• Materials Science

Background:

• Charge exchange dynamics are crucial for understanding ion-surface interactions.
• Low-energy ion scattering provides insights into electronic processes at surfaces.
• Molybdenum disulfide (MoS2) is a 2D material with unique electronic properties.

Purpose of the Study:

• To experimentally and theoretically investigate charge exchange dynamics in low-energy Li+ collisions with MoS2.
• To determine the neutralization fractions of backscattered Li+ projectiles.
• To elucidate the role of local electronic structure in resonant charge transfer.

Main Methods:

• Low-energy ion scattering experiments measuring charge-state-resolved time-of-flight spectra.
• Incident energies ranged from 2.5 to 8.0 keV.
• Theoretical modeling using a time-dependent resonant charge transfer model based on the Anderson Hamiltonian.

Main Results:

• Neutralization fractions for Li+ scattered from Mo atoms ranged from 20% to 35%.
• Neutralization showed a slight increase with energy and was attributed to single binary collisions.
• The theoretical model accurately reproduced the magnitude of neutralization but underestimated the energy dependence.

Conclusions:

• Local electronic structure significantly influences charge exchange processes.
• The study highlights the importance of considering excited states and multi-site interactions in theoretical models.
• Resonant charge transfer with Mo atoms is the dominant neutralization mechanism for Li+ on MoS2.