Electron states in a lattice of Au nanoparticles:: The role of strain and functionalization

We make use of first-principles calculations to study the effects of functionalization and compression on the electronic properties of 2D lattices of Au nanoparticles. We consider Au-38 particles capped by methylthiol molecules and possibly functionalized by the dithiolated conjugated molecules benzenedimethanethiol and benzenedicarbothialdehyde. We find that the nonfunctionalized lattices are insulating, with negligible band dispersions even for a compression of 20% of the lattice constant. Distinct behaviors of the dispersion of the lowest conduction band as a function of compression are predicted for functionalized lattices: The band dispersion of the benzenedimethanethiol-functionalized lattice increases considerably with compression, while that of the benzenedicarbothialdehyde-functionalized lattice decreases.