2016/04/30 by Run Yang, Bing Xu, Bîng Xu +5 · 3 citations
Chemistry · Materials Science · Physics and Astronomy · #Algorithm #Antiferromagnetism #Chemistry #Condensed matter physics #Crystallography #Iron-based superconductors research #Optical conductivity #Order (exchange) #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Rare-earth and actinide compounds #Spectroscopy #State (computer science) #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.93.245110
published in Physical review. B./Physical review. B 93(24) (American Physical Society) · 6 pages, 6 figures
arxiv created 2016/06/06 · openalex publication_date 2016/06/06 · arxiv updated 2016/06/15 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
In Ca_1\ensuremath-xRxFeAs2 (R=rare earth), an antiferromagnetic (AFM) phase as well as a structural transition have been reported, even in the electron-overdoped regime. Here, we investigated the temperature-dependent in-plane optical spectroscopy of overdoped Ca0.77Nd0.23FeAs2. Upon entering the AFM state, we found an abrupt reduction of low-frequency (500--2000 cm^\ensuremath-1) spectral weight in the optical conductivity. In sharp contrast to the parent compounds of the 122 system, where spin-density-wave gaps have been clearly observed in the AFM state, a gap signature is absent in Ca0.77Nd0.23FeAs2. This may be a consequence of the poor nesting condition between the hole and electron pockets. However, a spectral weight analysis shows that the reduced spectral weight at low frequency is transferred to the high-frequency range (\ensuremath\gtrsim4000 cm^\ensuremath-1), pointing to a localization effect. These observations suggest that the AFM order in Ca0.77Nd0.23FeAs2 is most likely to originate from a localized nature rather than Fermi-surface nesting.