Dirac electron-hole pairing gap in the heterostructure of ultra-thin films of topological insulator bilayer
Dirac electron-hole pairing gap in the heterostructure of ultra-thin films of topological insulator bilayer
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DOI：
10.1209/0295-5075/110/57002
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发表时间：
2015-06
期刊：
影响因子：
--
通讯作者：
Zhigang Wang;Z. Fu;Ping Zhang
中科院分区：
文献类型：
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作者：
Zhigang Wang;Z. Fu;Ping Zhang
在超越平均场近似的情况下，从理论上研究了由介质势垒隔开的拓扑绝缘体(TI)超薄膜系统中的电子-空穴配对能隙。结果表明，当考虑库仑关联效应和介质势垒的有限厚度效应时，配对能隙Δ被显著地抑制。然而，Δ可以通过每个TI超薄膜的上下表面态之间的耦合来增加。为了在实验上观察到更大的Δ，可能需要介电常数低得多的介电材料，如SiO_2基干凝胶薄膜。
The electron-hole pairing gap in a system of topological insulator (TI) ultra-thin film bilayer separated by a dielectric barrier is theoretically investigated beyond the mean-field approximation. We show that the pairing gap Δ is dramatically suppressed when accounting for the Coulomb correlation effect as well as the finite-thickness effect of the dielectric barrier. However, Δ can be increased by the coupling between the upper and lower surface states of each TI ultra-thin film. In order to observe much larger Δ in the present structure experimentally, the dielectric surrounding media materials with much lower dielectric constant, such as SiO2-based xerogel films, may be needed.