中文摘要：

采用基于密度泛函理论框架下的第一性原理平面波超软赝势方法，建立了N，Sm分别单掺杂以及Sm—N共掺杂的锐钛矿TiO2超胞模型，对其态密度、能带结构和吸收光谱进行了计算．结果表明：N单掺杂的锐钛矿TiO2的红移效果最强，但Sm—N共掺杂锐钛矿TiO2的载流子寿命更长，且共掺杂形成的体系更加稳定．

英文摘要：

Based on first principles within density-functional theory, we establish three models of N doped anatase TiO2, Sm doped anatase TiO2 and Sm-N codoped anatase TiO2 by using the plane-wave ultrasoft pseudopotential method. We calculate their densities of states, band structures and absorption spectra. Their results show that although the N doped anatase TiO2 takes the best redshift, the Sm-N codoped anatase TiO2 makes better lifespan of electron and the Sm-N codoped anatase TiO2 is more stable.