Title

Pentagraphite c8: An All- Sp2 Topological Nodal-Line Semimetal

Document Type

Article

Publication Date

12-15-2021

Publication Title

Physical Review B

Volume

104

Issue

24

Abstract

Recent research predicted stable two-dimensional pentagraphene in sp2-sp3 bonding states and three-dimensional pentadiamond (BC14) in all-sp3 bonding states, both comprising five-membered carbon-ring networks and exhibiting semiconducting character with sizable electronic band gaps. Here we identify by ab initio calculations an all-sp2 carbon allotrope, also comprising the unusual five-membered rings as the basic structural units, with an eight-atom monoclinic primitive cell in C2/m (C2h3) symmetry, termed mpg-C8 pentagraphite. Total-energy calculations show that mpg-C8 is more stable than or comparable to the previously reported all-sp2 rh6 polybenzene and all-sp3 BC14 pentadiamond. Electronic band calculations reveal that mpg-C8 is a topological nodal-line semimetal protected by the inversion (P) and time reversal (T) symmetry, comprising two nodal rings centered at the Γ and M points in the bulk first Brillouin zone and one projected surface flat band around the Fermi level on its (010) surface. These results establish a distinct type of carbon phase with nontrivial topological properties and offer insights into its outstanding electronic properties.

Controlled Subject

Science; Physics; Topological groups

Disciplines

Biological and Chemical Physics

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