Structural Stability, Electronic Structure, and Thermoelectric Properties for Half-Metallic Quaternary Heusler Compounds NdCoMnZ (Z = Al, In), PrCoMnZ (Z = Ga, In), and PrCoCrZ (Z = Al, Ga)

Abstract

Quaternary Heusler materials featuring intrinsic half-metallicity (HM) and high critical temperature Tc emerge as promising candidates for spintronic devices. The advanced density functional theory is used to examine the complicated interaction of the structural, electronic structure, and thermoelectric properties of novel NdCoMnZ (Z = Al, In), PrCoMnZ (Z = Ga, In), and PrCoCrZ (Z = Al, Ga) Quaternary Heusler compounds (QHAs). The total energies vs volume of the six materials were computed to formulate ground state characteristics. We have utilized TB-mBJ to estimate the band structure and density of states. The results show that the alloys are half metallic with considerable half-metallic gaps of 0.480 eV, 0.484 eV, 0.564 eV, 0.516 eV, 0.615 eV, and 0.580 eV for NdCoMnAl, NdCoMnIn, PrCoMnGa, PrCoMnIn, PrCoCrAl, and PrCoCrGa, respectively. All alloys have magnetic moments that are integers (5, 6, and 7 µ_B) and that satisfy the Pauli rule M_tot = (Z_tot-18). Our calculation of the Curie’s temperature T_C showed that the values range from 928 to 1290 K. The magnetic moments as a function of the lattice constant were also calculated for all materials. The thermoelectric properties of all materials are obtained using the BoltzTraB code based on Boltzmann transport theory. The Seebeck coefficient, electrical conductivity, electronic thermal conductivity, power factor, and figure of merit were calculated. The investigation of thermoelectric characteristics showed that both alloys display higher electrical conductivities and lower thermal conductivities.