Figure3 shows the calculated electronic properties as a function of electron carrier concentration n between 10 16 and 10 22 cm -3 for a fixed T = 1000 K, and as a function of temperature between 300-1200 K for a fixed n = 10 21 cm -3 . Pristine SrTiO 3 has a relatively low n on the order of 10 15 cm -3 , as expected for an insulator. However, depending on the preparation conditions, experimental samples can have a high concentration of oxygen vacancies which act as electron donors and produce a much higher n, and carrier concentrations as high as 3.5 × 10 20 cm -3 have been reported in undoped SrTiO 3 thin films. The chemical flexibility of the perovskite structure also allows it to accommodate a broad range of dopants that can enhance the n, yielding concentrations well in excess of 10 21 cm -3 in experiments. The fixed n = 10 21 cm -3 is therefore a conservative estimate of what should be possible in experiments. While perovskites are stable to high temperatures, we took T = 1000 K as a reference point to match the high-temperature heat-recovery scenario outlined in Ref. .