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采用原子簇嵌入模式的电荷自洽离散变分法(SCC-DV-X_a-ECM)对单斜型VO_2的电子结构和光电性质进行了计算。计算结果表明,单斜型VO_2带隙宽度为0.4411 eV,费米能级在带隙中间以上0.00365 eV靠近导带处,和实验数据符合得很好。单斜型VO_2的总能(-568.18 eV)比金红石型VO_2(-470.33 eV)小,说明外加能量如升高温度会使单斜型VO_2相变至金红石型VO_2。吸收系数在低频率段和实验情形符合得很好,光电导率在2.5～13.5 eV的变化趋势和其他的理论分析是一致的。
The electronic structures and photoelectric properties of monoclinic VO_2 have been calculated by self-consistent discrete variational method (SCC-DV-X_a-ECM) using the cluster insertion mode. The calculated results show that the width of the monoclinic VO_2 band gap is 0.4411 eV and the Fermi level is close to the conduction band at the 0.00365 eV above the middle of the band gap, which is in good agreement with the experimental data. The total energy of monoclinic VO_2 (-568.18 eV) is smaller than that of rutile VO_2 (-470.33 eV), indicating that the increase of the energy such as temperature increases the monoclinic VO_2 to rutile VO_2. The absorption coefficient is in good agreement with the experiment at low frequency. The trend of photoconductivity at 2.5 ~ 13.5 eV is consistent with other theoretical analyzes.