Evidence for a new class of solids. First-principles study of K(Al13)

The stability of the crystalline phase of a cluster-assembled solid K(Al13) has been investigated using first-principles total energy calculations. We find that K(Al13) may form in the CsCl structure with a lattice constant of 6.52 إ. Unlike the gas phase, in which the ground state of the Al13 cluster is icosahedral, the Al13 becomes cuboctahedral in the solid phase due to crystal field effects. The system is metallic and is stable against lattice distortions. The calculations suggest that a new metastable solid could be made from two immiscible elements through specially designed synthesis processes.