Structural, electronic, magnetic and thermoelectric properties of inverse Heusler alloys Ti2CoSi, Mn2CoAl and Cr2ZnSi by employing Ab initio calculations

The inverse Heusler alloys such as Ti2CoSi, Mn2CoAl and Cr2ZnSi were studied in the framework of density functional theory using FP-LAPW linearised augmented plane wave method in order to determine the different physical properties such as structural, electronic, magnetic and thermoelectric. The generalised gradient approximation (GGA) was used to treat the exchange–correlation energy and the Beck-Johnson (mBJ) approach was used to calculate the electronic properties. In all studied compounds, the stable type Hg2CuTi was energetically more favourable than Cu2MnAl type structure. The results show that two compounds (Ti2CoSi and Mn2CoAl) are both ferromagnetic (FM) while Cr2ZnSi is antiferromagnetic (AFM). The compounds Ti2CoSi and Mn2CoAl have a total magnetic moment of 3 and 2 μB, respectively, whereas the Cr2ZnSi alloy has a total magnetic moment equals zero. The Ti2CoSi, Mn2CoAl and Cr2ZnSi compounds exhibit half-metallic (HM) character with 100% spin polarisation at the Fermi level. Finally, the semi-classical Boltzmann theory implicit in the BoltzTraP code was used to calculate the electronic transport coefficients such as thermal and electrical conductivity, the Seebeck coefficient and the factor of merit.