Substrate-induced structures of bismuth adsorption on graphene: a first principles study

Abstract

The geometric and electronic properties of Bi-adsorbed monolayer graphene, enriched by the strong effect of a substrate, are investigated by first-principles calculations. The six-layered substrate, corrugated buffer layer, and slightly deformed monolayer graphene are all simulated. Adatom arrangements are thoroughly studied by analyzing the ground-state energies, bismuth adsorption energies, and Bi-Bi interaction energies of different adatom heights, inter-adatom distance, adsorption sites, and hexagonal positions. A hexagonal array of Bi atoms is dominated by the interactions between the buffer layer and the monolayer graphene. An increase in temperature can overcome a ∼50 meV energy barrier and induce triangular and rectangular nanoclusters. The most stable and metastable structures agree with the scanning tunneling microscopy measurements. The density of states exhibits a finite value at the Fermi level, a dip at ∼-0.2 eV, and a peak at ∼-0.6 eV, as observed in the experimental measurements of the tunneling conductance.

Featured properties of Li+-based battery anode: Li4Ti5O12

“…A theoretical framework based on rst-principles calculations 44 is developed for the essential properties of the 3D ternary compound Li 4 Ti 5 O 12 . The critical multi-orbital hybridizations in Li-O and Ti-O chemical bonds are delicately identied from the atom-dominated valence and conduction bands, the spatial charge density, and the atom-and orbital-decomposed density of states.…”

“…Very interestingly, chemical modications through adatom chemisorptions and guest-atom substitutions can greatly diversify various fundamental properties. 44 Apparently, the developed viewpoints are available in other condensed-matter systems. For example, they should be suitable for thoroughly exploring the diverse phenomena of Li +based battery anode/cathode/electrolyte materials.…”

“…For example, the rstprinciples calculations for band structures could be tted by the tight-binding model/the effective-mass approximation if the electronic energy spectra across the Fermi level are not so complicated. 44 This viewpoint has been very successful in fully examining the diversied essential properties of few-layer graphene systems, e.g. the diverse magnetic quantization of AA-, [45][46][47] AB-, 47,48 ABC- 49 and AAB-stacked graphenes under the generalized tight-binding model with any external elds.…”

“…28 In addition, the direct combination of numerical simulations with phenomenological models would be very useful to thoroughly understand the unusual and diverse properties, e.g. the linking of VASP calculations 21,22,44 and generalized tight-binding models 29 for rich magnetic quantization. 30 This paper is mainly focused on the geometric structure and electronic properties of the Li 4 Ti 5 O 12 -related anode material in Li + -based batteries.…”

Unusual features of nitrogen substitutions in silicene

“…The former is very successful in identifying the electronic structures of layered materials, e.g., the dimension-diversied energy bands in bulk graphites, 49 graphenes, 50 graphene nanoribbons, 51 and substrate-enriched few-layer group-IV systems. 52 The latter has conrmed the spin-resolved occupied energy sub-bands of topological insulators, 53 ferromagnetic materials, 54 and superconductors. 55 Experimental examinations of the nitrogen-substituted silicene systems can focus on the oscillatory energy dispersions near the Fermi level, the non-magnetic or ferromagnetic electronic states, the gapless or nite-gap band properties, and the modied/absent Dirac cone band structure at sufficiently low/high guest-atom concentrations.…”