Zigzag chain structure transition and orbital fluctuations in Ni-based superconductors

Youichi Yamakawa, Seiichiro Onari, Hiroshi Kontani

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


We investigate the electronic state and structure transition of BaNi 2As2, which shows a similar superconducting phase diagram as Fe-based superconductors. We construct the ten-orbital tight-binding model for BaNi2As2 by using the maximally localized Wannier function method. The Coulomb and quadrupole-quadrupole interactions are treated within the random-phase approximation. We obtain the strong developments of charge quadrupole susceptibilities driven by the in-plane and out-of-plane oscillations of Ni ions. The largest susceptibility is either Ox 2-y2-quadrupole susceptibility at q - (π0;π) or Oxz(yz)-quadrupole susceptibility at q - (πππ), depending on the level splitting between dX2-Y2 and dXZ(YZ). These antiferro-quadrupole fluctuations would then be the origin of the strong coupling superconductivity in Ni-based superconductors. Also, we propose that the antiferro-quadrupole OX2-Y2 order with q - (π 0; π) is the origin of the zigzag chain structure reported in experiments. We identify similarities and differences between Ni- and Fe-based superconductors.

Original languageEnglish
Article number094704
Journaljournal of the physical society of japan
Issue number9
Publication statusPublished - Sept 2013
Externally publishedYes


  • BaNiAs
  • Electron-phonon interaction
  • First-principles calculation
  • Orbital order
  • Pnictides
  • RPA
  • Structural phase transition

ASJC Scopus subject areas

  • General Physics and Astronomy


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