The effect of Ni/Co-doping on electronic structures and optical properties of cubic Ca2Ge

Improving the magnetic moment of Ca2Ge and promoting the conversion of semiconductors to diluted magnetic semiconductors using Mn-doping

“…Cubic phase Ca 2 Ge belongs to the Fm 3m space group with lattice constants a = b = c = 0.719 nm, and a = b = g = 90°. 22,23,[26][27][28] Each cell contains 8 Ca atoms and 4 Ge atoms. The doping model of Ca 8 Mn 1 Ge 3 is established by replacing a Ge with a Mn atom.…”

“…In order to form a stable state, the electron is transferred from the 4s orbital to the 3d orbital, forming a stable structure, 3d 1 4s 1 . 27 Due to the particularity of Ca 3d state electrons, it is speculated that there is a correlation between Ca 3d state electrons and Ge 3p state electrons in Ca 2 Ge compounds. The outer electron configuration of the central Ca ion is 3d 1 , and its unfilled d state electrons provide the valence bonding for the doped magnetic ions, forming a new electronic state, resulting in changes in the original electronic orbitals, electronic state, local structure, etc.…”