Calculation on Effect of Impurity Addition on Electronic State of $MnO_2$ Oxide Semiconductor by First Principle Moleculat Orbital Method

제1원리 분자궤도계산법에 의한 $MnO_2$ 산화물 반도체의 전자상태에 미치는 불순물 첨가 효과의 계산

The electronic structure of ${\beta}-MnO_2$ having impurities in the site of Mn was theoretically investigated by $DV-X_{\alpha}$ (the discrete variation $X{\alpha}$) method, which is a sort of the first principle molecular orbital method using Hatre-Fock-Slater approximation. The used cluster model was $[Mn_{14}MO_{56}]^{-52}$ (M = transient metals). Madelung potential and spin polarization were considered for more exact calculations. As results of calculations, the energy levels of all electron included in the model were obtained. The energy band gap and positions of impurity levies were discussed in association with impurity 34 orbital that seriously affect electrical properties of $MnO_2$. It was shown that the energy band gap decreased with the increase of the atomic number of transient metal impurity.