Eur. Phys. J. B (2014) 87: 24
https://doi.org/10.1140/epjb/e2013-40961-9

Regular Article

Half-metallicity and magnetism of the quaternary inverse full-Heusler alloy Ti_2-xM_xCoAl (M = Nb, V) from the first-principles calculations

¹ School of Physical Science and Technology, Southwest University, Chongqing 400715, P.R. China
² Department of Physics, Zunyi Normal College, Zunyi 563002, P.R. China

^a e-mail: chenh@swu.edu.cn

Received: 28 October 2013
Received in final form: 17 December 2013
Published online: 27 January 2014

Abstract

Using the first-principles calculations based on density functional theory, we investigate the more d-electrons doping effects on the electronic structure and magnetism of the parent inverse Heusler alloy Ti₂CoAl by the substitution of Nb and V atoms for Ti(A) and Ti(B) atoms locating at the two inequivalent sublattices. The Ti₂CoAl is half-metallic with Fermi level near the top of the minority-spin valence band and hence its spin-polarization is easily reduced by the spin-flip excitation. Our total energy calculations show that the V/Nb doping at the Ti(A)/Ti(B) site is energetically favorable compared with the Ti(B)/T(A) site due to the lower total energy. Our band structure calculations indicate that for the V doped compounds, half-metallicity can be well retained regardless of doping sites and percentages except for the case of Ti(A)-site doping with x = 1, while for Nb doped compounds, the half-metallicity persists only in Ti(B)-site doping with different percentages. For the doped compounds with half-metallicity, the Fermi level shifts from the top of minority-spin valence band to the bottom of minority-spin conduction band with increasing content of x, and typically, the doped compounds (V in Ti(A) and Ti(B) sites at x = 0.75 and 0.5, respectively; Nb in Ti(B) site at x = 0.5), whose Fermi levels are adjusted to the expected positions to effectively inhibit the spin-flip excitation are promising candidates for spintronics applications.