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arXiv · 2112.12324

Second-Order Real Nodal-Line Semimetal in Three-Dimensional Graphdiyne

Cong Chen·Xu-Tao Zeng·Ziyu Chen·Y. X. Zhao·Xian-Lei Sheng·Shengyuan A. Yang
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Abstract

Real topological phases featuring real Chern numbers and second-order boundary modes have been a focus of current research, but finding their material realization remains a challenge. Here, based on first-principles calculations and theoretical analysis, we reveal the already experimentally synthesized three-dimensional (3D) graphdiyne as the first realistic example of the recently proposed second-order real nodal-line semimetal. We show that the material hosts a pair of real nodal rings, each protected by two topological charges: a real Chern number and a 1D winding number. The two charges generate distinct topological boundary modes at distinct boundaries. The real Chern number leads to a pair of hinge Fermi arcs, whereas the winding number protects a double drumhead surface bands. We develop a low-energy model for 3D graphdiyne which captures the essential topological physics. Experimental aspects and possible topological transition to a 3D real Chern insulator phase are discussed.

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Cong Chen, Xu-Tao Zeng, Ziyu Chen, Y. X. Zhao, Xian-Lei Sheng, Shengyuan A. Yang. 2021-12-23. Second-Order Real Nodal-Line Semimetal in Three-Dimensional Graphdiyne. https://doi.org/10.1103/physrevlett.128.026405

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