Prediction of Novel Stable 2D-Silicon with Fivefold Coordination

Zhenhai Wang; Mingwen Zhao; Xiang-Feng Zhou; Qiang Zhu; Xiaoming Zhang; Huafeng Dong; Artem R. Oganov; Shumin He; Peter Grünberg

arXiv · 1511.08848

Prediction of Novel Stable 2D-Silicon with Fivefold Coordination

Zhenhai Wang·Mingwen Zhao·Xiang-Feng Zhou·Qiang Zhu·Xiaoming Zhang·Huafeng Dong·Artem R. Oganov·Shumin He·Peter Grünberg

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Abstract

Silicene, an analogue of graphene, was so far predicted to be the only two-dimensional silicon (2D-Si) with massless Dirac fermions. Here we predict a brand new 2D-Si Dirac semimetal, which we name siliconeet [silik'ni:t]. Unexpectedly, it has a much lower energy than silicene and robust direction-dependent Dirac cones with Fermi velocities comparable to those in graphene. Remarkably, its peculiar structure based on pentagonal rings and fivefold coordination plays a critical role in the novel electronic properties. Taking spin-orbit coupling into account, siliconeet can also be recognized as a 2D-topological insulator with a larger nontrivial band gap than silicene.

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Zhenhai Wang, Mingwen Zhao, Xiang-Feng Zhou, Qiang Zhu, Xiaoming Zhang, Huafeng Dong, Artem R. Oganov, Shumin He, Peter Grünberg. 2015-12-06. Prediction of Novel Stable 2D-Silicon with Fivefold Coordination. https://arxiv.org/abs/1511.08848

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