Fig. 1: Gibbs free energies and associated cumulative fraction sites of VS for the different configurations.
a Gibbs free energies of formation in the neutral (solid lines) and negatively charged (dashed lines) states of bare VS (green), (VS + N2) (blue) and (VS + O2) (red). The respective charge transition levels ϵ0/−1 are marked by vertical segments. b–d cumulative fraction of VS sites in neutral, θ0 (solid black line) or negatively charged, θ− (dashed black line) state, in different environmental conditions. b vacuum, c inert N2 atmosphere, d air (N2 + O2) atmosphere. The relative contributions of bare VS, (VS + N2) and (VS + O2) to the cumulative fraction of VS are shown by green, blue, and red areas, respectively.
