New Metallic Crystalline Carbon: Three Dimensionally PolymerizedC60Fullerite

We explore new polymerized ${\mathrm{C}}_{60}$ fullerite phases by using the total-energy calculations in the density-functional theory. Starting from the two dimensionally polymerized tetragonal phase, we find a new stable three dimensionally polymerized structure to be synthesized under uniaxial pressure of about 20 GPa. In sharp contrast to other polymerized ${\mathrm{C}}_{60}$ phases and to solid ${\mathrm{C}}_{60}$, the new polymer possesses metallic electronic structure with a relatively large Fermi-level density of states. Its conduction-electron distribution and the energetics are studied in detail.