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构建了SrTiO3(STO)薄膜在GaN基底(0001)表面沿不同方向偏转10^o、20^o、30^o、40^o和50^o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]SrTiO₃//[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^o时能量最低, 即外延关系为[1--10]SrTiO₃ //[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。

10?#20?#30?#40? and 50? in-plane rotation models of SrTiO3 (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]SrTiO3//[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.