First principles study of graphene on metals with the SCAN and SCAN+rVV10 functionals

Area of Science:

• Computational Materials Science
• Condensed Matter Physics
• Surface Science

Background:

• Graphene integration into electronic devices necessitates understanding its interaction with metal substrates and electrodes.
• Accurate theoretical modeling of graphene-metal interfaces is crucial for designing novel electronic applications.
• Existing semi-local functionals often fail to capture essential van der Waals interactions at these interfaces.

Purpose of the Study:

• To evaluate the performance of novel exchange-correlation functionals, specifically SCAN and SCAN+rVV10, in describing graphene-metal interactions.
• To investigate the binding energies, distances, and electronic band structures of graphene on fcc-metal(111) surfaces (M = Ni, Cu, Au).
• To compare the results obtained with SCAN-based functionals against other established methods like PBE and PBE-D3.

Main Methods:

• Ab initio calculations using density functional theory (DFT).
• Application of various exchange-correlation functionals: SCAN, SCAN+rVV10, PBE, PBE-D3, BEEF-vdW, and optB86b-vdW.
• Systematic investigation of graphene-fcc-metal(111) [Gr/M(111)] systems for M = Ni, Cu, Au.

Main Results:

• SCAN and SCAN+rVV10 successfully describe both chemisorption and physisorption on Gr/Ni(111), and physisorption on Gr/Cu(111) and Gr/Au(111).
• SCAN+rVV10 yields binding energies and distances comparable to experimental and random phase approximation results.
• Graphene doping (n-type on Cu, p-type on Au) and Dirac point modification on Ni due to electronic structure changes at the interface were observed.

Conclusions:

• SCAN and SCAN+rVV10 functionals offer improved accuracy for modeling van der Waals interactions in graphene-metal systems.
• The choice of functional and lattice parameter significantly impacts the description of adsorption on Gr/Ni(111).
• Understanding these interfacial electronic properties is key for tailoring graphene-based electronic devices.