Structural, electronic, magnetic and thermoelectric properties of full heusler alloys Co2YZ (Z = S, Ge, Se): A first principles calculation

Density functional theory (DFT) calculations are used to find physical characteristics of full Heusler (FH) alloys Co₂YZ (Z = S, Ge, Se). Full potential-linearized augmented plane wave (FP-LAPW) method within generalized gradient approximation (GGA) and Perdew-Burke-Ernzerhof functional is used. The results of phase stability have confirmed the stability of ferromagnetic (FM) phase as compared to anti-ferromagnetic (AFM), and nonmagnetic (NM) phases. The electronic properties show the half metallic (HM) character of Co₂YS and Co₂YSe by GGA. The role of on-site coulomb interaction (U) is also checked by GGA + U approach for Co₂YGe which confirmed its HM nature. The band diagrams are in accordance to density of states (DOS). The total magnetic moment (MM) of all alloys is 3μ_B which is in agreement to Slater-Pauling Rule (SPR)_. The spin polarization (SP) indicated that these materials are completely spin polarized. The Seebeck coefficient (S) and electrical conductivity (σ) are also calculated and discussed.