Bonding properties of Li2Ca and Mg2Ca

Theoretical indications of singular structural and electronic features of Laves-phase CaLi2 under pressure

In spite of the presence of ostensibly simple constituents, CaLi2 should be a very peculiar material under pressure. Its two 1-atmosphere polymorphs each undergo a structural bifurcation on densification to structures compressed or elongated in one lattice direction. A Hume-Rothery-type mechanism is proposed to account for the indicated lattice distortion. The narrowing of valence bands under pressure in this material, a large density of states at the Fermi level, and the expected high dynamical scales also hint at superconductivity.