Two-dimensional hexagonal M3C2 (M = Zn, Cd and Hg) monolayers: Novel quantum spin Hall insulators and Dirac cone materials

Peng Fei Liu, Liujiang Zhou, Sergei Tretiak, Li Ming Wu

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)

Abstract

The intriguing Dirac cones in honeycomb graphene have motivated the search for novel two-dimensional (2D) Dirac materials. Based on density functional theory and the global particle-swarm optimization method, herein, we predict a new family of 2D materials in honeycomb transition-metal carbides M3C2 (M = Zn, Cd and Hg) with intrinsic Dirac cones. The M3C2 monolayer is a kinetically stable state with a linear geometry (CMC), which to date has not been observed in other transition-metal-based 2D materials. The intrinsic Dirac cones in the Zn3C2, Cd3C2 and Hg3C2 monolayers arise from p-d band hybridizations. Importantly, the Hg3C2 monolayer is a room-temperature 2D topological insulator with a sizable energy gap of 44.3 meV. When an external strain is applied, additional phases with node-line semimetal states emerge in the M3C2 monolayer. These novel stable transition-metal-carbon-framework materials hold great promise for 2D electronic device applications.

Original languageEnglish
Pages (from-to)9181-9187
Number of pages7
JournalJournal of Materials Chemistry C
Volume5
Issue number35
DOIs
Publication statusPublished - 2017
Externally publishedYes

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