Half-metallic character and thermoelectric properties of the K2NaRbAs2 double half Heusler alloy.

This paper presents an investigation of the properties of the double half Heusler alloy (DHH) K₂NaRbAs₂. The structural, elastic, electronic, magnetic, and thermoelectric properties of the alloy are studied using the full-potential linearized augmented plane wave method (FP-LAPW) with the generalized gradient GGA approximation, and the GGA + Modified Becke-Johnson (mBJ) correlation potential is used to calculate the band structures and densities of states. The K₂NaRbAs₂ DHH alloy is derived from the previously studied parent half Heusler alloys KNaAs and KRbAs in their ferromagnetic phase of type I structure (FM-I). Our findings confirm the thermodynamic stability and synthesizability of K₂NaRbAs₂ in normal conditions. The alloy is shown to be resistant to distortion and able to withstand reversible deformation. The calculated elastic constants indicate that K₂NaRbAs₂ is mechanically stable, ductile, and anisotropic, as confirmed by 3D representation of its elastic moduli. Furthermore, the total magnetic moment of 2 µ_B demonstrates its half-metallic behavior, which mainly due to arsenic atoms. Like its parent alloys KNaAs, and KRbAs, the K₂NaRbAs₂ DHH alloy could be suitable for use in spintronic technology. Additionally, the thermoelectric characteristics of the K₂NaRbAs₂ DHH alloy are investigated using semi-classical Boltzmann transport theory, based on a smoothed Fourier interpolation of the bands, as implemented in the BoltzTraP package. [ABSTRACT FROM AUTHOR]