Layered Zintl phases at the verge of metallicity: metals, non-metals, semi-metals, and half-metals tuned by polar bonds (LAZIP)

High-pressure techniques and composition variations will be applied to specify mechanisms responsible for evolution of electronic structure and functional properties (giant magnetoresistance, thermopower) in the group of ternary compounds of U and Eu of the Zintl type (such as UCu₂P₂ and EuZn₂P₂) exhibiting important transfer of valence electrons from the f element to a compound anion. Such substances exhibit a band gap of tunable width and in UCu₂P₂ they can reach almost complete spin polarization at the Fermi level. That is maintained almost up to the Curie temperature, which is 216 K at normal conditions but dramatically increases at high pressures. Computational tools will be developed to account for the behavior of strongly correlated systems on the basis of uranium. Single-crystalline samples will be supplemented by sputter-deposited thin films, which can avoid certain limitations imposed by the equilibrium thermodynamics. Experimental techniques for bulk properties will be accompanied by electron spectroscopies.