中文摘要：

运用第一性原理方法，研究了拓扑绝缘体Bi2Se3块体和薄膜中的层堆垛对其结构、电子态、拓扑态和自旋劈裂的影响。发现不同的堆垛会引起Bi2Se3层间的相互作用，改变系统的中心对称性。块体的ABC和AAA堆垛都具有中心对称性和相似的能带结构。 ABA堆垛破坏了体系的中心对称性，能带发生很大改变，并且产生了很大的能带自旋劈裂。用能带反转的方法判定体系的拓扑相，在不同堆垛的Bi2Se3块体中，考虑自旋轨道耦合时都发生了能带反转，因而具有不同堆垛的Bi2Se3仍是拓扑绝缘体。进一步研究了Bi2Se3薄膜中的堆垛效应，发现非中心对称的ABA堆垛在Bi2 Se3薄膜中引起明显的自旋劈裂，并且提出和验证了用应变调控自旋劈裂的方法。

英文摘要：

By using first-principles method, we study the stacking effects on the electronic structure, topological phase and spin splitting in the bulk and film of topological insulator Bi2Se3. It is found that the different stackings can lead to different interlayer interactions and change the centrosymmetry of Bi2Se3. The centrosymmetric ABC and AAA stackings in bulk Bi2Se3 have similar band structures. ABA stacking breaks the centrosymmetry, giving rise to considerable changes of the band structure and large spin splitting. We further study the stacking effects in the film of Bi2Se3 and find that the non-centrosymmetric ABA stacking can induce large spin splitting in Bi2Se3 film. It is proposed and illustrated that the strain can tune the spin splitting effectively.