Electronic structure, phase stability, equation of state, and pressure-dependent superconducting properties of Zr3Al

Abstract

We report here the ambient and high-pressure electronic-structure calculations of the potentially important ordered intermetallic alloy Zr3Al obtained using the self-consistent linear muffin-tin orbitals (LMTO) method. Further total-energy calculations were made using the tight-binding LMTO scheme in the L12 and DO19 phases in order to study its structural stability. From total-energy studies and the band filling of bonding states results, we conclude that it is easier to create instability in the L12 lattice of Zr3Al and this prediction is consistent with the experimentally observed martensitic structural transition from DO19→L12 structure. To make a comparative study, the band structure and total-energy calculations of isoelectronic Ti3Al were also made. The calculated bulk modulus and its pressure derivative, determined using a universal equation of state, are reported. The nature of chemical bonding in Zr3Al is also discussed. Using the band-structure results, within the BCS formalism, the superconducting transition temperature (Tc) was calculated and it is compared with the experimental value. The ambient-pressure band-structure, and Tc calculations of the A15 compound Nb3Al were made with a view to compare its superconducting behavior with that of Zr3Al at high pressures as Zr3Al should mimic Nb3Al at high pressures. The pressure dependence of Tc of Zr3Al is analyzed. Our calculations on Zr3Al are in contradiction with the often quoted correlation between the low density of states at the Fermi level and structural stability in similar systems and this is further corroborated with our more recent studies on Ti3In and Ni3In.

Source-reported materials — not catalogue approval

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