Tomsk State University , pr. Lenina 36, 634050 Tomsk, Russia.
Nano Lett. 2013;13(12):6064-9. doi: 10.1021/nl403312y. Epub 2013 Dec 2.
The ability to engineer an electronic band structure of topological insulators would allow the production of topological materials with tailor-made properties. Using ab initio calculations, we show a promising way to control the conducting surface state in topological insulator based heterostructures representing an insulator ultrathin films on the topological insulator substrates. Because of a specific relation between work functions and band gaps of the topological insulator substrate and the insulator ultrathin film overlayer, a sizable shift of the Dirac point occurs resulting in a significant increase in the number of the topological surface state charge carriers as compared to that of the substrate itself. Such an effect can also be realized by applying the external electric field that allows a gradual tuning of the topological surface state. A simultaneous use of both approaches makes it possible to obtain a topological insulator based heterostructure with a highly tunable topological surface state.
通过工程化拓扑绝缘体的能带结构，可以制造出具有定制性能的拓扑材料。我们使用第一性原理计算，展示了一种很有前途的控制基于拓扑绝缘体的异质结构中导电表面态的方法，这种异质结构代表了拓扑绝缘体衬底上的超薄绝缘层。由于拓扑绝缘体衬底和超薄绝缘层覆盖层的功函数和带隙之间存在特定的关系，狄拉克点会发生相当大的位移，导致拓扑表面态载流子的数量显著增加，比衬底本身的数量还要多。通过施加外部电场也可以实现这种效应，这允许对拓扑表面态进行逐渐调谐。同时使用这两种方法，可以获得具有高度可调谐拓扑表面态的基于拓扑绝缘体的异质结构。
