First-principles study of C6B2

Kazuaki Kobayashi, Yuji Zenitani, Jun Akimitsu

Research output: Contribution to journalConference article

3 Citations (Scopus)

Abstract

We calculate the electronic and lattice properties of C6B 2 (Na3As type crystal structure) using the first-principles molecular dynamics (FPMD) method. C6B2 is a hypothetical hexagonal compound, which consists of two B-C layers and two C-C layers. All calculated electronic band structures are metallic. C 6B2 has unoccupied flat bands close to the Fermi level at the Γ-A line. These flat bands correspond to unoccupied σ-bands of MgB2 at the Γ-A line. Displacements of B atoms along a B-C bond split unoccupied flat bands at the Γ-A line into two subbands. A total energy change with displacements of B atoms indicates anharmonicity of a B-C stretching mode. We investigate C6B2 under various compression conditions. The change in the electronic band structure under a, b-axis compression (Pxy) is small. In contrast, it is quite remarkable under c-axis compression (Pz). We find the lattice anomaly of C6B2 under a, b-axis compression. This anomaly shows a kind of negative Poisson ratios.

Original languageEnglish
Pages (from-to)374-380
Number of pages7
JournalPhysica C: Superconductivity and its applications
Volume426-431
Issue numberI
DOIs
Publication statusPublished - Oct 1 2005
Externally publishedYes
EventProceedings of the 17th International Symposium on Superconductivity (ISS 2004) Advances in Supeconductivity -
Duration: Nov 23 2004Nov 25 2004

Keywords

  • CB
  • Electronic band structure
  • First principles
  • Lattice anomaly

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering

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