Chinese Physics B, Volume. 29, Issue 10, (2020)

Evidence for bosonic mode coupling in electron dynamics of LiFeAs superconductor

Cong Li1...2, Guangyang Dai1,2, Yongqing Cai1,2, Yang Wang1,2, Xiancheng Wang1,2, Qiang Gao1,2, Guodong Liu1, Yuan Huang1, Qingyan Wang1, Fengfeng Zhang3, Shenjin Zhang3, Feng Yang3, Zhimin Wang3, Qinjun Peng3, Zuyan Xu3, Changqing Jin1,2,4, Lin Zhao1,†, and X J Zhou1,2,45 |Show fewer author(s)
Author Affiliations
  • 1Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 0090, China
  • 2University of Chinese Academy of Sciences, Beijing 100049, China
  • 3Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
  • 4Songshan Lake Materials Laboratory, Dongguan 523808, China
  • 5Beijing Academy of Quantum Information Sciences, Beijing 100193, China
  • show less
    Figures & Tables(4)
    Electronic structure of LiFeAs measured under different polarization geometries. (a) Overall Fermi surface of LiFeAs measured with a photon energy of 21.218 eV. Two Fermi surface sheets observed around Γ are labeled as β (blue circle) and γ (pink circle), while two crossing elliptical Fermi surface sheets observed around M point are labeled as δ (black ellipses). (b)–(d) Fermi surface of LiFeAs measured by using laser ARPES with a photon energy of 6.994 eV under different polarization geometries. The directions of the electric field vector E corresponding to the three polarization geometries are marked by double arrows in the bottom-right corner of each panel. We note that, while the electric field vector E in (c) fully lies in the sample plane, there is some component of the electric field vector E that is outside of the sample plane in (b) and (d). In (b), the α band is also marked (dashed green circle) around Γ in addition to the β and γ Fermi surfaces. (e)–(g) The band structure of LiFeAs measured along the Γ–X direction under three different polarization geometries that correspond to (b)–(d), respectively. The location of the momentum cut is marked in (b) by a red line. The green, blue, and pink arrows point to the α, β, and γ bands, respectively.
    Electron dynamics of the γ band of LiFeAs measured along the Γ–X direction at 20 K. (a) The γ band measured along the Γ–X direction. The location of the momentum cut is marked by the red line in the inset. (b) The second derivative image of (a) with respect to energy. (c) Second derivative image of the simulated single-particle spectral function which considers electron coupling with two bosonic modes at 20 meV and 34 meV. (d) Momentum distribution curves (MDCs) at several representative binding energies. The MDCs are fitted by Loretzians that are overlaid as dashed lines on the measured data. (e) Representative energy distribution curves (EDCs) at several momenta. (f) Dispersion relation obtained by MDC fitting. The dashed red and blue lines represent empirical bare bands that are used to get the effective real parts of the electron self-energy Re Σ (red line and blue line) shown in (g). The observed features are marked by pink, green, and orange strips. (h) Corresponding MDC width (full width at half maximum, FWHM) of the γ band in (a) from the MDC fitting.
    Electron dynamics of the β band of LiFeAs measured along the Γ–X direction at 20 K. (a) The β band measured along the Γ–X direction. The location of the momentum cut is marked by the red line in the inset. (b) The second derivative image of (a) with respect to energy. (c) MDCs at several representative binding energies. The MDCs are fitted by Loretzians that are overlaid as dashed lines on the measured data. (d) Representative EDCs at several momenta. (e) Dispersion relation obtained by MDC fitting. The dashed red and blue lines represent empirical bare bands that are used to get the effective real parts of the electron self-energy, Re Σ, (red line and blue line) shown in (f). The observed features are marked by pink, green, and orange strips. (g) Corresponding MDC width (FWHM) of the β band in (a) from the MDC fitting.
    Temperature dependence of the electron dynamics for the β and γ bands in LiFeAs. (a) Temperature dependent effective real part of electron self-energy of the γ band. For clarity, the curves are offset along the vertical axis. (b) Corresponding MDC width of the γ band measured at different temperatures. The upper-right inset shows the MDC width near the EF region. (c) EDCs measured at the kF point of the γ band at different temperatures. The EDC at 12 K is also multiplied by 5 times to show the dip structure near 34 meV as marked by an arrow. The upper-left inset shows the temperature dependence of the EDC width (FWHM) of the γ band. (d) Temperature dependent effective real part of electron self-energy of the β band. The curves are offset along the vertical axis for clarity. (e) Corresponding MDC width of the γ band measured at different temperatures. The upper-right inset shows the MDC width near the EF region. (f) EDCs measured at the kF point of the β band at different temperatures. The upper-left inset shows the temperature dependence of the EDC width (FWHM) of the β band.
    Tools

    Get Citation

    Copy Citation Text

    Cong Li, Guangyang Dai, Yongqing Cai, Yang Wang, Xiancheng Wang, Qiang Gao, Guodong Liu, Yuan Huang, Qingyan Wang, Fengfeng Zhang, Shenjin Zhang, Feng Yang, Zhimin Wang, Qinjun Peng, Zuyan Xu, Changqing Jin, Lin Zhao, X J Zhou. Evidence for bosonic mode coupling in electron dynamics of LiFeAs superconductor[J]. Chinese Physics B, 2020, 29(10):

    Download Citation

    EndNote(RIS)BibTexPlain Text
    Save article for my favorites
    Paper Information

    Category: Rapid Communication

    Received: Aug. 14, 2020

    Accepted: --

    Published Online: Apr. 21, 2021

    The Author Email: Zhao Lin (XJZhou@iphy.ac.cn)

    DOI:10.1088/1674-1056/abb21f

    Topics