Atomic structure and electronic properties of Ag(111)/TiC(111) interface: Insights from first-principles simulations

The atomic and electronic structures of Ag(111)/TiC(111) interfaces with two atomic terminals and eight stacking sites models were studied by first-principles method. The calculated results of the bulk properties of fcc Ag and TiC are in agreement with the experimental results, showing that the parameters used here are reliable. Moreover, the results of surface energy demonstrate that the Ti-terminated TiC(111) surface is more stable than the C-terminated TiC(111) surface. It is found that the bridge site (BS) interface was converted into the hcp site (HS) interface after optimization, proving that the BS site interface type does not exist. The results of adhesion energy and interfacial energy indicate that the C-terminated interfaces are more stable than Ti-terminated interfaces. The C-FS-Ag interface is the most stable in the six different Ag(111)/TiC(111) interfaces since the C-FS-Ag interface has the highest adhesion energy (2.93 J/m2) and the lowest interfacial energy (−13.26 ∼ −11.47 J/m2). The charge density difference and the partial density of states (PDOS) results show that the Ti-terminals interfaces have weak metal bond binding, while the C-terminals interfaces has a combination of ionic bonds and covalent bonds. The C-FS-Ag interface has more charge accumulation and stronger interaction.