Figure 2

(a) The enthalpy of mixing curve highlights the intermediate composition (c) with respect to the end member compositions (b,d), where the x-axis is the concentration of Cs in the occupied A-sites. (b–d) Calculated energy with respect to (wrt) the minimum B-site configuration for a range of Zn-hollandite configurations, where the tables indicate the arrangement of B-site dopants within a tunnel layer (rows) or along the tunnel direction (columns). Note that the enthalpy of mixing energies (a) are the same as the energies reported in (b) and (d), but only similar to that reported in (c), where the minimum configuration for the energy comparison is the intermediate composition rather than the end-member composition(s).