Influence of Mn doping on magneto-thermoelectric properties of spintronic material ZnMnxSn1-xAs2

In present investigation a comprehensive spin-polarized density functional theory (DFT) analysis of Mn-doped ZnSnAs₂ chalcopyrite carried out by utilizing the Full-Potential Linearized Augmented Plane Wave (FP-LAPW) method with Tran-Blaha’s modified Becke-Johnson (TB-mBJ) functional. Electronic, magnetic, and thermoelectric properties of doped ZnMn${}_x$Sn${}_{(1-x)}$As${}_2$ investigated within the doping range $0\le x\le 0.5$. Mn doping at Sn site induces a significant spin magnetic moment, leading to a half-metallic and high-spin ferromagnetic state. With increasing Mn concentration, the majority spin state retains bandgap while the minority spin state behaves like a degenerate semiconductor. This results an overall increase in magnetic moment and making the material promising for spintronic applications. This study also explores thermoelectric properties using Boltzmann transport theory within the constant scattering time approximation. The key thermoelectric parameters, including the Seebeck coefficient (S), electrical conductivity ($\sigma$), and electronic thermal conductivity ($\kappa$) were evaluated as functions of temperature and doping concentrations. Mn doping enhances the thermoelectric performance and we get highest Figure of merit (ZT) nearly 1.2 at 500 K for higher Mn concentrations. Spin-dependent contributions play a crucial role, minority-spin state exhibiting higher specific heat (${\text{C}}_v$) and power factor (PF) values as compared with majority-spin states. These findings suggest that Mn doping not only boosts the spintronic application of Mn doped ZnSnAs₂ but also enhances thermoelectric efficiency of the materials and may be utilized for energy conversion applications.