Insulator-to-Conductor Transition in Warm Dense Neon

In contrast to the high-density behavior of most materials, the band gap of neon is predicted to increase with density at a wide range of conditions in both solid and fluid states [1-2]. We combine static and dynamic compression to study fluid Ne at densities up to ~6.5 g/cm³ and temperatures approaching ~100,000 K. We observe a novel trend in the reflectivity of shocked Ne, which indicates that at these conditions, the reflectivity and conductivity of Ne decrease with increasing density, supporting the band gap prediction. The results suggest that Ne remains insulating in the interiors of giant planets such as Jupiter and showcase the exotic material properties that can emerge in the warm dense matter regime. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0003856.

[1] J. Tang, et al., Physics of Plasmas 24, 082709 (2017).

[2] J. Tang, et al., J. Chem. Phys. 150, 111103 (2019).