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Orbital design of topological insulators from two-dimensional semiconductors


Two-dimensional (2D) materials have attracted much attention because they exhibit various intrinsic properties, which are, however, usually not interchangeable. Here we propose a generic approach to convert 2D semiconductors to 2D topological insulators (TIs) via atomic adsorption. The approach is underlined by an orbital design principle that involves introducing an extrinsic s-orbital state of the adsorbate into the intrinsic sp-bands of a 2D semiconductor, so as to induce s-p band inversion for a TI phase, as demonstrated by tight-binding model analyses. Based on first-principles calculations, we successfully apply this approach to convert CuS, CuSe and CuTe into TIs by adsorbing Na, Na0.5K0.5 and K as well as Rb and Cs one adatom per unit cell. Moreover, if the chalcogens in the 2D semiconductor have a decreasing ability of accepting electrons, the adsorbates should have an increasing ability of donating electrons. Our findings open a new door to discovering TIs by predictive materials design beyond finding preexisting TIs.

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Publication details

The article was received on 09 Aug 2019, accepted on 25 Oct 2019 and first published on 28 Oct 2019

Article type: Communication
DOI: 10.1039/C9NR06859G
Nanoscale, 2019, Accepted Manuscript

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    Orbital design of topological insulators from two-dimensional semiconductors

    L. Gao, J. Sun, G. Sethi, Y. Zhang, S. Du and F. Liu, Nanoscale, 2019, Accepted Manuscript , DOI: 10.1039/C9NR06859G

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