e/a dependence of the lattice instability of cubic Heusler alloys from first principles

摘要

First-principles calculations are used to investigate chemical trends in the structural instability of the high-symmetry cubic structure for a selected set of ferromagnetic Heusler compounds. The role of the valence-electron-to-atom ratio e/a is investigated both by comparing compounds of different compositions, and by artificially changing the electron density in the first-principles calculations. Systematic trends in the interatomic force constant, previously found to be an indicator of the structural instability, are identified and discussed.