Half-metallicity and onsite Hubbard interaction on d-electronic states: a case study of Fe₂NiZ (Z = Al, Ga, Si, Ge) Heusler systems

ABSTRACT

DFT-based structural optimisations of Fe₂NiZ (Z = Al, Ga, Si, Ge) Heusler compounds confirm the stability of these alloys in F-43m phase. While defining the electronic structure, onsite Hubbard approximation scheme for exchange correlations predicted better results than the generalised gradient approximation. Calculated band structure and densities of states together with spin magnetic moments designate the half-metallic character of these alloys. Indirect band gaps, 1.2 eV for Fe₂NiAl, 0.98 eV for Fe₂NiGa, 1.3 eV for Fe₂NiSi and 1.1 eV for Fe₂NiGe in spin-down states are observed. The ferromagnetic spin moments amount to an integral value of 5μB for (Al, Ga) and 6μB for (Si, Ge) systems with a maximum contribution from transition metal atom (Fe). To forecast the possible turnout of the thermopower, Seebeck coefficients, electrical and thermal conductivities are calculated, which directly hints the thermoelectric response of these materials. This study creates a possibility of these alloys in thermoelectrics and spintronics.

KEYWORDS:

• Electronic structure
• Heusler alloys
• half-metallic
• ferromagnetic materials
• Seebeck coefficient

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Author K.M. Batoo and M Khan are thankful to the Deanship of Scientific Research at King Saud University for its funding through the Research Group Project No. RG-1437-030.