Electronic structure and elastic properties of the Ni3X (X=Mn, Al, Ga, Si, Ge) intermetallics

Phys. Rev. B 54, 14413 – Published 15 November 1996
Dobrina Iotova, Nicholas Kioussis, and Say Peng Lim

Abstract

First-principles total-energy electronic structure calculations based on the full-potential linear-muffin-tin-orbital method have been used to study the electronic and mechanical properties of the L12-type ordered nickel-based intermetallics Ni3X (X=Mn, Al, Ga, Si, Ge). The calculated values for the equilibrium volume and elastic properties are generally in good agreement with experiments. The large shear anisotropy factor across the series is attributed to the anisotropy of the bonding charge density, which can be described by the combination of charge transfer from X to Ni and strong X p–Ni d (Mn d–Ni d in Ni3Mn) hybridization effect. The more pronounced directional bonding between the Ni and Si atoms compared to that between the Ni and Al atoms, and the small (large) redistribution of bonding charge in Ni3Al (Ni3Si) when the systems are under shear strain result in a stronger resistance to a shear for Ni3Si. The bonding charge densities for Ni3Ga and Ni3Ge are found to be similar to those for Ni3Al and Ni3Si, respectively. These results suggest that the addition of the extra p electron on the X atom increases the directionality of the bonding. The change of bonding charge directionality in Ni3Mn is due to the Mn d–Ni d hybridization. The calculated ratio of bulk to shear modulus of polycrystalline systems, B/G, proposed by Pugh to provide a simple rule of measuring the ease of plastic deformation, is found to correlate well with the absolute difference in the s-orbital electronegativity between the atomic constituents, and the difference in energy, Ed(Ni)-Ep(X) [Ed(Ni)-Ed(Mn) for Ni3Mn], across the series. © 1996 The American Physical Society.

DOI: http://dx.doi.org/10.1103/PhysRevB.54.14413

  • Received 10 May 1996
  • Published in the issue dated 15 November 1996

© 1996 The American Physical Society

Authors & Affiliations

Dobrina Iotova, Nicholas Kioussis, and Say Peng Lim

  • Department of Physics and Astronomy, California State University Northridge, Northridge, California 91330-8268

References (Subscription Required)

Authorization Required


×
×

Images

×

Log In

Cancel
×

Search


Article Lookup
Paste a citation or DOI

Enter a citation
×
  1. Enter a citation to look up or terms to search.

    Ex: "PRL 112 068103", "Phys. Rev. Lett. 112, 068103", "10.1103/PhysRevLett.112.068103"