Superconducting and Superhard Ice

Abstract

Superconducting and superhard materials are essential for a myriad of scientific, biomedical and industrial applications. The contradiction between covalent bonds in superhard materials and metallic bonds in superconductors makes superconductivity and superhardness in the same material a very interesting and precious effect. Their abilities of zero-resistance and anti-pressure stem from the relationship between the crystal structure, chemical composition, and microstructure. The complexity of this interdependence limits researchers to conduct comprehensive experimental investigations, but can be supported by the theoretical calculations. Here, we report a general ab initio computational method to study three ice structures (Pmc21 , P21 and C2/m) and predict their phase transitions quantitatively at terapascal pressure. We predict that the ice structure will become a superhard material above 1.3 TPa (corresponding to P21 and C2/m), and turn into a superconductor above 5.0 TPa (corresponding to C2/m) with a critical temperature of 1.782 K. The proposed work benefits the applications of low temperature superconductors in high energy physics and fusion research and provides opportunities to advance the development of superconducting and superhard materials through computation.