Bosonic spectrum of a correlated multiband system, BaFe1.80Co0.20As2, obtained via infrared spectroscopy

• Published in: Results in physics 2023-07, Vol.50, p.106572, Article 106572
• Main Authors: Panda, Chandan Kumar, Lee, Hong Gu, Park, Hwiwoo, Jung, Soon-Gil, Choi, Ki-Young, Hwang, Jungseek
• Format: Article
• Language: English
• Subjects: Bosonic spectrum; Co-doped Ba122; Extended Drude–Lorentz model; Fe-pnictides; Optical conductivity; Two-parallel-channel approach
• ISSN: 2211-3797; 2211-3797
• DOI: 10.1016/j.rinp.2023.106572

We investigated a single crystal BaFe2−xCoxAs2 (Co-doped BaFe2As2: Co-doped Ba122) with x=0.20 using infrared spectroscopy. We obtained the bosonic spectrum from the measured spectrum using an extended Drude–Lorentz model for the normal state and a two-parallel-channel approach for the superconducting (SC) state, based on the generalized Allen formula. The coupling constant, maximum SC transition temperature, SC coherence length, and upper critical field were extracted from the bosonic spectrum. The superfluid plasma frequency and the London penetration depth were obtained from the optical conductivity. We compared the physical quantities of Co-doped Ba122 and K-doped Ba122 and found some interesting differences. Our results may be helpful for understanding superconductivity in doped Ba122 systems and may provide useful information on doped Ba122 systems for their applications. •Bosonic spectra of Co-doped Ba122 at 8 and 27 K were extracted from measured optical conductivity.•Various physical quantities were obtained from the bosonic spectrum.•Maximum SC Tc obtained from the bosonic spectrum is larger than Tc measured by DC transport.•The physical quantities of the Co-doped Ba122 were compared with those of K-doped Ba122.