报告题目：2D vdWs topological insulators

报告人：寇良志博士 昆士兰科技大学

报告时间：2016年6月17日 14:30

报告地点：知新楼C座10楼研究生讨论室

邀请人：戴瑛 教授 

报告摘要：

Although there are extensive predicted 2D topological insulators theoretically, the nontrivial gap is too small for practical applications, especialy graphene which is predicted to possess 10^-3 meV nontrivial gap. Constructing van der Waals structure is a feasible solution, which can not only protect the vulnerable surface, but also enhance the spin orbit coupling (leading to QSH phase) due to the proximity effect when choose a suitable substrate. Take graphene as an example, we demonstrated from first principles calculations that, when sandwiched between two cladding layers, graphene can be turned into 2D topological insulators with nontrivial gap from 2-120 meV depending on the chosen substrate (Bi₂Se₃, MoTe₂, or BiTeI)^1-3. It provides a feasible approach to use graphene for innovative QSH device designs.

References

(1) L. Kou, B. Yan, F. Hu, S. C. Wu, T. O. Wehling, C. Felser, C. Chen, T. Frauenheim, "Graphene-Based Topological Insulator with an Intrisinc Bulk Gap above Room Temperature" Nano Lett., 2013, 13, 6251-6255.

(2) L. Kou, F. Hu, B. Yan, T. O. Wehling, C. Felser, T. Frauenheim, C. Chen, "Proximity Enhanced Quantum Spin Hall State in Graphene" Carbon, 2015, 87, 418-423.

(3) L. Kou, S. C. Wu, C. Felser, T. Frauenheim,C. Chen, B. Yan, "Robust 2D Topological Insulators in van der Waals Heterostructures" ACS Nano, 2014, 8, 10448-10454. 

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