Second-Order Real Nodal-Line Semimetal in Three-Dimensional Graphdiyne
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.
- Publication:
-
Physical Review Letters
- Pub Date:
- January 2022
- DOI:
- 10.1103/PhysRevLett.128.026405
- arXiv:
- arXiv:2112.12324
- Bibcode:
- 2022PhRvL.128b6405C
- Keywords:
-
- Condensed Matter - Materials Science;
- Condensed Matter - Mesoscale and Nanoscale Physics
- E-Print:
- 8 pages, 4+4 figures. Accepted for publication in Physical Review Letters