Honeycomb Boron Allotropes with Dirac Cones: A True Analogue to Graphene

We propose a series of planar boron allotropes with honeycomb topology and demonstrate that their band structures exhibit Dirac cones at the K point, the same as graphene. In particular, the Dirac point of one honeycomb boron sheet locates precisely on the Fermi level, rendering it as a topologicall...

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Bibliographic Details
Published in:The journal of physical chemistry letters 2017-06, Vol.8 (12), p.2647-2653
Main Authors: Yi, Wen-cai, Liu, Wei, Botana, Jorge, Zhao, Lei, Liu, Zhen, Liu, Jing-yao, Miao, Mao-sheng
Format: Article
Language:English
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Summary:We propose a series of planar boron allotropes with honeycomb topology and demonstrate that their band structures exhibit Dirac cones at the K point, the same as graphene. In particular, the Dirac point of one honeycomb boron sheet locates precisely on the Fermi level, rendering it as a topologically equivalent material to graphene. Its Fermi velocity (v f) is 6.05 × 105 m/s, close to that of graphene. Although the freestanding honeycomb B allotropes are higher in energy than α-sheet, our calculations show that a metal substrate can greatly stabilize these new allotropes. They are actually more stable than α-sheet sheet on the Ag(111) surface. Furthermore, we find that the honeycomb borons form low-energy nanoribbons that may open gaps or exhibit strong ferromagnetism at the two edges in contrast to the antiferromagnetic coupling of the graphene nanoribbon edges.
ISSN:1948-7185
1948-7185
DOI:10.1021/acs.jpclett.7b00891