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基于平面波赝势密度泛函理论,研究了La,Ce,Nd掺杂SnO2的电子结构和光学性质。计算结果表明,La附近的键长变化最大,而Nd附近的键长变化最小,这表明稀土掺杂SnO2引起的晶格畸变与掺杂原子的共价半径大小有关。能带结构表明,稀土掺杂可使SnO2的带隙变窄。La掺杂相比较本征SnO2,带隙减小了0.892 e V,Nd掺杂在SnO2的禁带中引入了3个能级。差分电荷密度分析表明,稀土掺杂使SnO2的电子重新分配且由于f电子的存在使其离子性增强。La原子失电子最多,Nd原子失电子最少,这和计算的能带结果是一致的。光学性质表明,介电函数的虚部和吸收函数因稀土掺杂出现了不同程度的红移,这和计算的能带结果非常吻合。
The electronic structures and optical properties of La, Ce, Nd-doped SnO2 have been studied based on the planar wave pseudopotential density functional theory. The calculated results show that the bond length near La is the largest and the bond length near Nd is the smallest, which indicates that the lattice distortion caused by rare earth doped SnO2 is related to the covalent radius of doped atoms. Band structure shows that rare earth doped SnO 2 can narrow the bandgap. Compared with intrinsic SnO2, the bandgap of La doped is reduced by 0.892 eV, and Nd doping introduces three energy levels in the forbidden band of SnO2. Differential charge density analysis showed that rare earth doping led to the redistribution of SnO2 electrons and the enhancement of ionicity due to the presence of f electrons. La atom has the largest electron loss and Nd atom has the least electron loss, which is consistent with the calculated band. Optical properties show that the imaginary part of the dielectric function and the absorption function due to rare earth doping show varying degrees of redshift, which is in good agreement with the calculated bandgap results.