Quantum-mechanical interference in charge exchange between hydrogen and graphene-like surfaces

Area of Science:

• Surface science
• Quantum mechanics
• Condensed matter physics

Background:

• Understanding charge dynamics of atoms on surfaces is crucial for surface chemistry and catalysis.
• Graphene's unique electronic properties, including its band structure, influence atom-surface interactions.
• Previous studies on hydrogen-graphene interactions often simplified the electronic interplay.

Purpose of the Study:

• To calculate the charge fluctuation of a hydrogen atom near a graphene surface.
• To investigate the role of quantum mechanical interference and Berry phase in hydrogen-graphene interactions.
• To explain the observed negative ion formation in proton-graphite scattering experiments.

Main Methods:

• Utilizing the Anderson model with infinite intra-atomic Coulomb repulsion approximation.
• Performing ab initio calculations of the Anderson hybridization function.
• Analyzing the impact of hydrogen interacting with multiple carbon atoms on graphene.

Main Results:

• A marked asymmetry in the imaginary part of the hybridization function relative to the Fermi level was found.
• Predicted Fano factors greater than one, showing strong energy dependence near the Fermi level.
• Demonstrated that hybridization suppression above the Fermi level explains negative ion formation.

Conclusions:

• The study provides a theoretical explanation for negative hydrogen ion formation on graphene surfaces.
• Quantum interference effects, particularly Berry phase, significantly influence hydrogen atom charge states on graphene.
• The findings have implications for understanding atom-surface interactions and designing novel electronic devices.