Pressure induced structural instability of FeV intermetallic compound with B2 ordering

Abstract

The structural, elastic, lattice dynamic, and electronic properties of intermetallic FeV with B2 ordering under hydrostatic pressure are extensively investigated by using the first-principles calculations within density functional theory. The calculated lattice constant, bulk modulus, magnetic moment, and number of electronic states at the Fermi level at P = 0GPa are in a good agreement with the previous calculated and experimental results. The elastic moduli show linearly increasing trends with pressure, except shear modulus which shows a linear softening trend. The transverse acoustic (TA) phonon mode propagating along the [110] direction polarized along the [11-0] direction decreases to be imaginary crossing the critical pressure ∼9.4 GPa, resulting in the structural instability of B2-FeV intermetallic. Comparing the phonon softening with the shear modulus softening, it is suggested that the soft phonon mode dominates the pressure-induced structural instability of B2-FeV. The electronic density of state (DOS) shows that a considerable increase in the number of electronic states at the Fermi level with increasing pressure, and this behavior is consistent with the phonon softening.