Y掺杂SrTiO3晶体材料的电子结构计算

采用基于第一性原理的密度泛函理论平面波超软赝势法, 研究了Y掺杂SrTiO₃体系的空间结构和电子结构性质, 得到了优化后体系的结构参数, 掺杂形成能, 能带结构和电子态密度. 对比掺杂浓度为0125, 025, 033时，Sr_1-xY_xTiO₃和SrTi_1-xY_xO₃的掺杂形成能，发现Y替代Sr能形成更稳定的结构. 对Sr_1-xY_xTiO₃（x=0, 0125, 025, 033） 的结构进行了优化，结果表明Y替代Sr后, 随着掺杂浓度增大, 体系的晶格常数逐渐减小, 稳定性逐渐增强. 对不同掺杂浓度的Sr_1-xY_xTiO₃能带结构的计算结果表明：纯净的SrTiO₃是绝缘体, 价带顶在R点, 导带底在Γ点, 费米能级处于价带顶; 掺杂Y后, 费米能级进入到导带底中, 体系呈金属性；掺杂浓度越大，费米能级进入导带的位置越深，禁带宽度也近似变宽. 关键词： 3')" href="#">SrTiO₃ 电子结构 掺杂 VASP

Calculation of the electronic structure of Y-doped SrTiO3

The geometrical and electronic structures, and also the dopant formation energies, lattice constants, band structure and density of states （DOS） of Sr_1-xY_xTiO₃ with x=00, 0125, 025 and 033 are calculated from the first principles of plane wave ultra-soft pseudo-potential method based on density functional theory. The results of dopant formation energy show that Y preferentially enters the Sr site in SrTiO₃ Electronic structure results show that pure SrTiO₃ is an insulator and the Fermi energy is at the top of valence band. When doped with Y, the Fermi energy of the system goes into the conduction band and the system undergoes an insulator-to-metal transition. Due to the appearance of the carrier impurity from Y doping, there is a significant distortion near the bottommost conduction bands.