Comment on "Topological Nodal-Net Semimetal in a Graphene Network Structure"

Abstract

Recently, a distinct topological semimetal, nodal-net semimetal, has been identified by Wang et al. through ab initio calculations [Phys. Rev. Lett. 120, 026402 (2018)]. The authors claimed that a new body-centered tetragonal carbon allotrope with I4/mmm symmetry, termed bct-C40, can host this novel state exhibiting boxed-astrisk shaped nodal nets. In this Comment, we demonstrate that bct-C40 is in fact a nodal surface semimetal, the concept of which has been proposed as early as 2016 [Phys. Rev. B 93, 085427 (2016)].

Although the quasi-nodal surface has been identified in our preprint, there is a tiny band gap (millivolt-level) in the non high symmetry k-line (e.g.,K1-K5). In this regard, the proposed bct-C40 should be a nodal net semimetal based on the strict definition of topological semimetal. We would like to withdraw this work to avoid misleading the readers from Arxiv