Evolution from Topological Nodal Points to Nodal Line: Realized in Fused Carbon Allotrope

Herein, via first‐principle calculations and theoretical analysis, a new Dirac semimetal carbon system called C32, which is composed of pentagonal, hexagonal, heptagonal, and octagonal carbon rings is systematically investigated. The stability of C32 is verified by calculating the phonon dispersion,...

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Bibliographic Details
Published in:	Physica status solidi. PSS-RRL. Rapid research letters Vol. 18; no. 9
Main Authors:	Xing, Jinhui, Yue, Wentao, Yuan, Jiaren, Zhang, Lizhi, Wei, Yingcong, Zhang, Lichuan, Xie, Yuee, Chen, Yuanping
Format:	Journal Article
Language:	English
Published:	Weinheim Wiley Subscription Services, Inc 01-09-2024
Subjects:	Allotropy Carbon Cones Dirac semimetals Elastic anisotropy Elastic properties graphane phase transition tight‐binding model Topology
Online Access:	Get full text
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Summary:	Herein, via first‐principle calculations and theoretical analysis, a new Dirac semimetal carbon system called C32, which is composed of pentagonal, hexagonal, heptagonal, and octagonal carbon rings is systematically investigated. The stability of C32 is verified by calculating the phonon dispersion, elastic constants, etc., and an appropriate pathway for experimental synthesis is proposed. Besides, it is discovered that the system holds the quadruple rotation and inversion symmetry, resulting in the emergence of eight twisted Dirac cones (D1 and D2) with a highly anisotropic Fermi velocity from 3.83 × 105 to 8.96 × 105 m s−1 along different k directions. To substantiate the semimetallic nature of C32, its nontrivial topological properties are confirmed through the presence of topologically protected edge states, and the nonzero ℤ2 topological invariant. More importantly, by introducing biaxial strain, it is uncovered that Dirac cones can gradually evolve into a nodal line, and the perfect nodal line can be obtained when the biaxial strain is 13.3%. Furthermore, by constructing the tight‐binding model, the appearance of the Dirac cone is perfectly repeated and its evolution into the nodal line under biaxial strain is explained. A new two‐dimensional anisotropic Dirac semimetallic carbon system is predicated according to the first‐principle calculation, and the band structure can be modulated from the Dirac semimetal to nodal line through strain engineering. The evolution of the band structure is explained by the tight‐binding model, and a feasible chemical synthesis scheme is proposed to make the system.
ISSN:	1862-6254 1862-6270
DOI:	10.1002/pssr.202400095