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Ultrafast Optical Spectroscopy Evidence of Pseudogap and Electron-Phonon Coupling in an Iron-Based Superconductor KCa$_2$Fe$_4$As$_4$F$_2$
- Source :
- Sci. China-Phys. Mech. Astron.65, 237411(2022)
- Publication Year :
- 2021
-
Abstract
- We use ultrafast optical spectroscopy to study the nonequilibrium quasiparticle relaxation dynamics of the iron-based superconductor KCa$_2$Fe$_4$As$_4$F$_2$ with $T_c=33.5$ K. Our results reveal a possible pseudogap ($\Delta_{PG}$ = 2.4 $\pm$ 0.1 meV) below $T^*\approx 50$ K but prior to the opening of a superconducting gap ($\Delta_{SC}$(0) $\approx$ 4.3 $\pm$ 0.1 meV). Measurements under high pump fluence real two distinct, coherent phonon oscillations with 1.95 and 5.51 THz frequencies, respectively. The high-frequency $A_{1g}$(2) mode corresponds to the $c-$axis polarized vibrations of FeAs planes with a nominal electron-phonon coupling constant $\lambda_{A_{1g}(2)}$ = 0.194 $\pm$ 0.02. Our findings suggest that the pseudogap is likely a precursor of superconductivity, and the electron-phonon coupling may play an essential role in the superconducting pairing in KCa$_2$Fe$_4$As$_4$F$_2$.<br />Comment: 6 pages, 3 figure
- Subjects :
- Condensed Matter - Superconductivity
Subjects
Details
- Database :
- arXiv
- Journal :
- Sci. China-Phys. Mech. Astron.65, 237411(2022)
- Publication Type :
- Report
- Accession number :
- edsarx.2109.06460
- Document Type :
- Working Paper
- Full Text :
- https://doi.org/10.1007/s11433-021-1830-9