Observation of iron d-orbitals modifications in superconducting FeSe by Raman spectra study

H. I. Hsiung, W. H. Chao, H. Y. Hsu, M. J. Wang, H. L. Liu, M. K. Wu*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


We have studied the Raman spectra of superconducting FeSe and non-superconducting Cu-doped FeSe crystals at different temperatures. The spectral range covers the phonon modes at low frequency regime to electronic Raman scattering at high frequency regime, up to 2000 cm−1. A hardening in frequency of B1g mode, which is related to the spin-phonon coupling is observed. At high frequency region, our results on superconducting FeSe crystal show that the dzx and dyz orbitals of Fe split at ∼130 K and then become closer to achieve balance as temperature decreases. This result indicates that a modification of d-orbital electron state of iron happens at temperature much higher than the structural transition, implicating a precursor order in iron-based superconductor. In comparison with non-superconducting Cu0.03Fe0.97Se crystal, our observations suggest that the orbital modification could be an important clue for understanding the mechanism of superconductivity in iron-based superconductors.

Original languageEnglish
Pages (from-to)61-63
Number of pages3
JournalPhysica C: Superconductivity and its applications
Publication statusPublished - 2018 Sept 15


  • FeSe superconductor
  • Phonon modes
  • Raman spectroscopy
  • Structural distortion

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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