Ab-initio evaluation of Mn doped Cs₂GeCl/Br₆ halides for spintronics and energy harvesting applications

We utilized Ab-initio calculations to study electronic, structural, magnetic, and thermoelectric characteristics for Cs₂GeCl/Br₆ halides that were either undoped or doped with Manganese (Mn). We evaluated the total energy variation among ferromagnetic (FM) and antiferromagnetic (AFM) phases to determine the ferromagnetic structural stability of Mn-doped Cs₂GeCl/Br₆ halides. In addition, structural stability also justified through the calculations of elastic properties. To make precise predictions about the electronic properties of both undoped and Mn-doped Cs₂GeCl/Br₆ halides, we used modified Becke-Johnson local density approximation functional. Mn-doped Cs₂GeCl/Br₆ halides demonstrated FM semiconducting behavior, as indicated by their band structures and density of states plots, which are reported by magnetic moments and crystal field splitting energies. We systematically explored the thermoelectric characteristics by calculating parameters such as electrical and thermal conductivities, Seebeck coefficient, and Figure of merits. The Mn-doped Cs₂GeCl/Br₆ halides demonstrated a large value for Figure of merit and inconsequential lattice thermal conductivity, making them particularly suitable for thermoelectric applications.