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arXiv · 1706.03293

Three-dimensional Pentagon Carbon with a genesis of emergent fermions

Chengyong Zhong·Yuanping Chen·Zhi-Ming Yu·Yuee Xie·Han Wang·Shengyuan A. Yang·Shengbai Zhang
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Abstract

Carbon, the basic building block of our universe, enjoys a vast number of allotropic structures. Owing to its bonding characteristic, most carbon allotropes possess the motif of hexagonal rings. Here, with first-principles calculations, we discover a new metastable three-dimensional carbon allotrope entirely composed of pentagon rings. The unique structure of this "Pentagon Carbon" leads to extraordinary electronic properties, making it a cornucopia of emergent topological fermions. Under lattice strain, Pentagon Carbon exhibits topological phase transitions, generating a series of novel quasiparticles, from isospin-1 triplet fermions, to triply-degenerate fermions, and further to concatenated Weyl-loop fermions. Its Landau level spectrum also exhibits distinct features, including a huge number of almost degenerate chiral Landau bands, implying pronounced magneto-transport signals. Our work not only discovers a remarkable carbon allotrope with highly rare structural motifs, it also reveals a fascinating hierarchical particle genesis with novel topological fermions beyond the Dirac and Weyl paradigm.

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Chengyong Zhong, Yuanping Chen, Zhi-Ming Yu, Yuee Xie, Han Wang, Shengyuan A. Yang, Shengbai Zhang. 2017-06-11. Three-dimensional Pentagon Carbon with a genesis of emergent fermions. https://doi.org/10.1038/ncomms15641

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