Effect of transition metal (TM: Cr and Mn) doping on charge transport properties of ScNiBi: A density functional theory approach

First principles approach has been employed to study the effect of transition metal (TM) doping on electronic, magnetic and thermoelectric properties of ScNiBi (SNB). Modification in electronic structure has been made by doping of Cr/Mn atoms in SNB at Ni site to enhance the Seebeck coefficient and hence the thermoelectric performance. Through density-functional theory calculations of Cr/Mn-substituted where X=Cr and Mn, we have demonstrated that strong resonant level near the Fermi energy has been induced by d-states of the substituted TM atoms and paramagnetic state of SNB becomes ferromagnetic material upon doping. Spin polarized electronic structure of ScNi _0.5 Cr _0.5 Bi and ScNi _0.5 Mn _0.5 Bi (SNCB and SNMB hereafter) making it suitable candidate for spintronic applications.The maximum value of Seebeck coefficient of SNB, SNCB and SNMB at room temperature was observed to be 33.4 × 10^-5 VK^-1, 114.2 × 10^-5 VK^-1 and 72.2 × 10^-5 VK^-1 respectively. On the other hand the maximum electrical conductivity for SNB, SNCB and SNMB at room temperature was found to be 1.34 × 10¹⁸Ω ms^-1, 2.27 × 10¹⁶Ω ms^-1 and 2.82 × 10¹⁷Ω ms^-1 respectively.