Searching for the 2D layered phases of carbon dioxide at multimegabar pressures

Despite the paramount importance of carbon dioxide as a simple system and also as a geophysical relevant material, the experimental investigations are limited so far only up to 120 GPa. Our research proposal is to study the phase diagram of carbon dioxide at extreme pressures. We would like to perform a detailed and extensive study of carbon dioxide between 100 and 300 GPa at room and at high temperatures by laser heating in order to investigate the stability field of carbon dioxide under geothermal conditions. In addition we propose to discover the transition from the 3D extended phase V (beta-cristobalite I-42d) to a new layered 2D phase with carbon still in 4 fold coordination (layer-AB P42/nmc or layer-AA P-4m2) which is expected to become stable above 200 GPa as obtained by several simulations studies.