Three-dimensional Pentagon Carbon with a genesis of emergent fermions.
Three-dimensional Pentagon Carbon with a genesis of emergent fermions.
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三维五边形碳与涌现费米子的起源
DOI：
10.1038/ncomms15641
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发表时间：
2017-06-05
影响因子：
16.6
通讯作者：
Zhang S
中科院分区：
文献类型：
--
作者：
Zhong C;Chen Y;Yu ZM;Xie Y;Wang H;Yang SA;Zhang S
碳是宇宙的基本组成部分，具有大量的同素异形结构。由于其键合特性，大多数碳同素异形体都具有六角环的图案。在这里，通过第一性原理计算，我们发现了一种新的完全由五边形环组成的亚稳态三维碳同素异形体。这种五边形碳的独特结构带来了非凡的电子特性，使其成为新兴拓扑费米子的聚宝盆。在晶格应变下，五角形碳表现出拓扑相变，产生一系列新型准粒子，从同位旋 1 三重态费米子到三重简并费米子，再到 Hopf-link Weyl-loop 费米子。其朗道能级谱也表现出明显的特征，包括大量几乎简并的手性朗道带，这意味着明显的磁输运信号。我们的工作不仅发现了一种具有高度罕见结构图案的非凡碳同素异形体，还揭示了一种令人着迷的分层粒子起源，具有超越狄拉克和外尔范式的新型拓扑费米子。碳同素异形体是否可以容纳新出现的拓扑费米子尚不清楚。在这里，钟等人。预测完全由五边形环组成的三维碳同素异形体，显示出在应变下的大量拓扑费米子。
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 Hopf-link 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. Whether carbon allotropes may host emergent topological fermions is unknown. Here, Zhong et al. predict a three-dimensional carbon allotrope entirely composed of pentagon rings, showing a plethora of topological fermions under strain.