Ab initio studies of the structural, electronic and magnetic properties of stannite CuFe2-III-VI4 (III = Al, Ga, In and VI = S, Se, Te) alloys

Abstract

The structural, magnetic and electronic properties of stannite CuFe2-III-VI4 (where III = Al, Ga, In and VI = S, Se, Te) quaternary alloys were investigated using the full-potential augmented plane wave and local states approach as implemented in the Wien2K. The effects of exchange and correlation functional were parameterized according to the generalized gradient approximation (GGA) and GGA + U approaches. The calculated lattice constants for these alloys are in reasonable agreement with available experimental data. We find that the band gap width decreases as the anion atomic number increase in the CuFe2-III-VI4 alloys while keeping the cation unchanged. The electronic density of states reveals different electronic character such as half-semiconducting, half-metallic and metallic depending on the cation (group III atom) or anion (group VI atom) considered. The magnetic moments within the GGA + U approach, for all the alloys considered (CuFe2AlS4, CuFe2AlSe4, CuFe2AlTe4, CuFe2GaS4, CuFe2GaSe4, CuFe2InS4, CuFe2InSe4 and CuFe2InTe4) are 8 μB except for CuFe2GaTe4 alloy, which is 7.95 μB. The observed magnetism in these alloys is mainly from the 3d states of Cu and Fe atoms. In conclusion, the study presents a theoretical investigation on the CuFe2-III-VI4 alloys within the GGA and GGA + U approaches.