Electronic structure study of triangular lattices in FeGa2 S4, Fe2 Ga2 S5, and NiGa2 S4: Photoemission spectroscopy and Hartree-Fock calculations

K. Takubo, T. Mizokawa, Yusuke Nambu, S. Nakatsuji

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

We have studied the electronic structure of the Fe and Ni triangular lattices in FeGa2 S4, Fe2 Ga2 S5, and NiGa2 S4 using photoemission spectroscopy measurements, configuration-interaction calculations on FeS6 and NiS6 cluster models, and unrestricted Hartree-Fock calculations on FeS2 and NiS2 triangular lattices. The cluster-model analysis of the Fe2p core-level spectra shows that the S3p to Fe3d charge-transfer energy Δ is ∼2.5 eV in FeGa2 S4 and Fe2 Ga2 S5, in contrast to the small Δ (∼-1 eV) found in NiGa2 S4. The relationship between the Δ value and the superexchange pathway has been examined using the unrestricted Hartree-Fock calculations. In FeGa2 S4 and Fe2 Ga2 S5, the superexchange interaction between the nearest-neighbor sites is dominant while that between the third-nearest-neighbor sites is enhanced in NiGa2 S4.

Original languageEnglish
Article number134422
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume79
Issue number13
DOIs
Publication statusPublished - 2009 Apr 20
Externally publishedYes

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

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