中文摘要：

构建了SrTiO_3（STO）薄膜在GaN基底（0001）表面沿不同方向偏转10°、20°、30°、40°和50°具有不同界面结构的生长模型,采用基于密度泛函理论的平面波超软赝势法对GaN（0001）表面外延生长不同方向的STO进行了总能量模拟计算。结果表明,在晶格失配小的理想外延方向即[1-10]SrTiO_3//[10-10]GaN的能量最高,结构不稳定;而随着STO[1-10]沿GaN[10-10]方向角度的偏转,能量迅速降低,偏转角度为30°时能量最低,即外延关系为[1-10]SrTiO_3//[11-20]GaN时最稳定,与实验结果一致.能量计算结果表明,STO/GaN磁电薄膜有利于形成STO-Ti-GaN的界面结构。

英文摘要：

10°、20°、30°、40°and 50°in-plane rotation models of SrTiO_3（STO） films on GaN（0001） substrates with different interface structure were designed.The total energies of different epitaxial models of STO/GaN magnetoelectric films were theoretically explored by the plane wave ultra soft pseudo-potential model based on density functional theory.The simulated results show that STO films grown on GaN（0001） substrates with the ideal（with the lowest lattice mismatch） epitaxial relation of[1-10]SrTiO_3//[10-10]GaN have the highest energy,indicating this unstable configuration.The total energies become lower quickly with the rotation of STO[1-10]along GaN[10-10]direction,showing the lowest energy at the 30°rotation, which are the most stable structures.The epitaxial orientation relations are[1-10]SrTiO3//[11-20]GaN by this 30°rotation in the in-plane direction of the STO epilayer on GaN（0001） substrates,which are in agreement with experimental observation.Calculation results also reveal that the STO/GaN magnetelectric film is favor in forming STO-Ti-GaN interface structure.