Fig. 4: Direct current electrical conductivity of SiO₂ in the Mbar regime.

a DC electrical conductivity of silica (colour scale) as a function of temperature and pressure. Coloured squares are our experimental double-shock data. The grey crosses show the error bars on our data as one standard deviation of the distribution obtained via a Monte-Carlo method (see the Supplementary Notes 6 for details). Sparse data are calculations from Mazevet et al.⁹ (reversed triangles) and Scipioni et al.⁷ (carved squares). The T–P relation along the fused silica and stishovite Hugoniot curves are from Mazevet et al.⁹ and Millot et al.¹⁰, respectively. The static conductivity along the fused silica and α-quartz Hugoniot has been estimated by applying our method to reflectivity and equation-of-state data in the literature^10,16. Melting lines as in Fig. 2. b SiO₂ DC electrical conductivity as a function of pressure along three different quasi-isothermal lines, extracted from the data-set presented in panel a. Data from Mazevet et al.⁹ and Scipioni et al.⁷ (personal communication of the pressure values) are also shown, with thick and thin dashed lines, respectively, marking isothermal paths as a guide to the eye. The dashed lines follow the same colour code as the data-sets.