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目的研究La掺杂对SrTiO_3体系电子结构和导电性的影响。方法采用基于密度泛函理论(DFT)框架下的第一性原理平面波超软赝势方法。结果La掺杂后,体系总体态密度只是向低能方向进行了刚性平移,费米能级进入导带,简并化加剧,刚性能带模型仍然适用于Sr_(1-x)La_xTiO_3体系;由于Burstein-Moss移动效应,光学带隙明显展宽,在导带底出现大量由La原子贡献的自由载流子-电子,改善了SrTiO_3的导电性能。结论La掺杂对SrTiO_3的导电性起着非常重要的作用。
Aim To study the effect of La doping on the electronic structure and electrical conductivity of SrTiO_3 system. Methods First-principles plane-wave ultra-soft pseudopotential method based on density functional theory (DFT) was used. Results After La doping, the overall state density of the system translates into a rigid translation in the direction of low energy, the Fermi level enters the conduction band and the degeneracy aggravates. The rigid band model is still suitable for the Sr_ (1-x) La_xTiO_3 system. Since Burstein -Moss movement effect. The optical band gap broadens obviously. A large number of free carriers - electrons contributed by La atoms appear at the bottom of the conduction band, improving the conductivity of SrTiO_3. Conclusion La doping plays a very important role in the electrical conductivity of SrTiO_3.