2025/12/02 by K. Koshiishi, L. Liu, Koshiishi, K. +29
Materials Science · Physics and Astronomy · #Iron-based superconductors research #Magnetic and transport properties of perovskites and related materials #Physics of Superconductivity and Magnetism
paper · pdf · doi:10.48550/arxiv.2512.02488
The microscopic origin of the nematicity, namely, four-fold rotational symmetry breaking in iron-based superconductors has been controversial since its discovery. In particular, its relationship with the stripe-type spin-density-wave order and the orthorhombic lattice distortion in the antiferromagnetic orthorhombic (AFO) phase, which exists at temperatures below the electronic nematic phase, has been highly debated. Here, we report on the temperature evolution of angle-resolved photoemission spectra of the parent compound BaFe2As2, ranging from the AFO to nematic to paramagnetic phases. The Dirac cone feature, which is formed in the AFO phase, is found to persist in the nematic phase, suggesting that an antiferroic order of the same periodicity as the AFO phase persists in the nematic phase. Considering the relatively shallow dxy orbital in BaFe2As2, we propose that an antiferro-orbital order involving the dxy and other orbitals takes place in the nematic phase.