Metal segregation and electronic properties of lithium suboxide clusters

Abstract

The structural and electronic properties of neutral lithium suboxide clusters ${\mathrm{Li}}_{4+p}{\mathrm{O}}_{2}$ $(0<~p<~9)$ are studied by means of ab initio molecular dynamics simulations. For few excess Li atoms Li-O bonds are formed which progressively weaken as the O coordination number increases. Then Li attachment proceeds around nonstoichiometric ionic cores and results in metal segregation. The evolution of the growth mode correlates with a change of the electronic properties, some of which can be probed experimentally to obtain structural information. We predict that at small $p$ ${\mathrm{Li}}_{4+p}{\mathrm{O}}_{2}$ clusters have ionization potential much lower than pure ${\mathrm{Li}}_{p}.$ A generalization of our results to oxidized alkali-metal surfaces and bulk suboxides is proposed.