We present a structural and density functional theory study of Fe_xCu_1−xSe within the three-dimensional topological insulator Bi₂Te₃. The Fe_xCu_1−xSe inclusions are single-crystalline and epitaxially oriented with respect to the Bi₂Te₃ thin film. Aberration-corrected scanning transmission electron microscopy and electron energy loss spectroscopy show an atomically sharp Fe_ICu_1−xSe/Bi₂Te₃ interface. The Fe_xCu_1−xSe/Bi₂Te₃ interface is determined by Se–Te bonds and no misfit dislocations are observed, despite the different lattice symmetries and large lattice mismatch of ∼19%. First-principle calculations show that the large strain at the Fe_xCu_1−xSe/Bi₂Te₃ interface can be accommodated by van der Waals-like bonding between Se and Te atoms.

我们提出了三维拓扑绝缘体Bi ₂ Te ₃中Fe _x Cu _{1− x} Se的结构和密度泛函理论研究。Fe _x Cu _{1- x} Se夹杂物是单晶的，并且相对于Bi ₂ Te ₃薄膜外延取向。像差校正的扫描透射电子显微镜和电子能量损失谱显示原子上清晰的Fe _I Cu _{1- x} Se / Bi ₂ Te ₃界面。Fe _x Cu _{1− x} Se / Bi ₂Te ₃界面由Se–Te键决定，尽管晶格对称性不同且晶格失配率约为19％，但未观察到失配位错。第一性原理计算表明，Fe _x Cu _{1− x} Se / Bi ₂ Te ₃界面处的大应变可以通过Se和Te原子之间的范德华式键合来适应。