Ultrafast Optical Spectroscopy Evidence of Pseudogap and Electron-Phonon Coupling in an Iron-Based Superconductor KCa${}_2$Fe${}_4$As${}_4$F${}_2$

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 $T^{\ast }\approx 50$ 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${}_2$.

arXiv comment6 pages, 3 figure

References in corpus (46)

• Angle-resolved photoemission spectroscopy of the cuprate superconductors
• A Common Thread: the pairing interaction for the unconventional superconductors
• Density functional study of FeS, FeSe and FeTe: Electronic structure, magnetism, phonons and superconductivity
• Antiferromagnetic order and spin dynamics in iron-based superconductors
• Interfacial mode coupling as the origin of the enhancement of Tc in FeSe films on SrTiO3
• Is LaO${}_{1-x}$F${}_x$FeAs an electron-phonon superconductor ?
• Ultrafast optical spectroscopy of strongly correlated materials and high-temperature superconductors: a non-equilibrium approach
• Quasiparticle relaxation dynamics in superconductors with different gap structures: theory and experiments on YBa_{2}Cu_{3}O_{7-δ}
• The effect of collective spin-1 excitations on electronic spectra in high-Tc superconductors
• Progress in Neutron Scattering Studies of Spin Excitations in High-Tc Cuprates
• Multiple Nodeless Superconducting Gaps in (Ba0.6K0.4)Fe2As2 Superconductor from Angle-Resolved Photoemission Spectroscopy
• Electron-Phonon Coupling in High-Temperature Cuprate Superconductors Determined from Electron Relaxation Rates
• Superconductivity in KCa${}_2$Fe${}_4$As${}_4$F${}_2$ with Separate Double Fe${}_2$As${}_2$ Layers
• Electron-lattice interaction and its impact on high Tc superconductivity
• Electron relaxation in metals: Theory and exact analytical solutions
• Ultrafast dynamics of coherent optical phonons and nonequilibrium electrons in transition metals
• Ultrafast Dynamics Evidence of High Temperature Superconductivity in Single Unit Cell FeSe on SrTiO3
• Fermi surface dichotomy of the superconducting gap and pseudogap in underdoped pnictides
• Quasiparticle relaxation dynamics in heavy fermion compounds
• Band-dependent Quasiparticle Dynamics in Single Crystals of the Ba${}_{0.6}$K${}_{0.4}$Fe${}_2$As${}_2$ Superconductor Revealed by Pump-Probe Spectroscopy
• Quasiparticle dynamics and phonon softening in FeSe superconductors
• Lattice and electronic anomalies of CaFe_2As_2 studied by Raman spectroscopy
• Quasiparticle relaxation dynamics in spin-density-wave and superconducting SmFeAsO_{1-x}F_{x} single crystals
• Visualizing the microscopic coexistence of spin density wave and superconductivity in underdoped NaFe1-xCoxAs
• Electron-phonon coupling and charge gap in spin-density-wave iron-pnictides from quasiparticle relaxation dynamics
• Neutron spin resonance in a quasi-two-dimensional iron-based superconductor
• Doping dependence of femtosecond quasi-particle relaxation dynamics in Ba(Fe,Co)_2As_2 single crystals: possible evidence for normal state nematic fluctuations
• Ultrafast Quasiparticle Dynamics and Electron-Phonon Coupling in (Li0.84Fe0.16)OHFe0.98Se
• Nodal multigap superconductivity in KCa${}_2$Fe${}_4$As${}_4$F${}_2$
• Single-crystal growth and extremely high H_c2 of 12442-type Fe-based superconductor KCa_2Fe_4As_4F_2
• Odd and even modes of neutron spin resonance in the bilayer iron-based superconductor CaKFe${}_4$As${}_4$
• Ultrafast quasiparticle relaxation dynamics in normal metals and heavy fermion materials
• Spectroscopic Evidence of Bilayer Splitting and Interlayer Pairing in an Iron Based Superconductor
• Neutron spin resonance in the 112-type iron-based superconductor
• Nonequilibrium Quasiparticle Relaxation Dynamics in Single Crystals of Hole and Electron doped BaFe${}_2$As${}_2$
• Friedel Oscillations of Vortex Bound States Under Extreme Quantum Limit in KCa2Fe4As4F2
• Strong Pauli paramagnetic effect in the upper critical field of KCa${}_2$Fe${}_4$As${}_4$F${}_2$
• NMR and NQR studies on transition-metal arsenide superconductors LaRu2As2, KCa2Fe4As4F2, and A2Cr3As3
• Band-selective clean- and dirty-limit superconductivity with nodeless gaps in the bilayer iron-based superconductor CsCa${}_2$Fe${}_4$As${}_4$F${}_2$
• Single particle tunneling spectroscopy and superconducting gaps in layered iron based superconductor KCa${}_2$Fe${}_4$As${}_4$F${}_2$
• Low temperature specific heat of 12442-type KCa_2Fe_4As_4F_2 single crystals
• Anisotropic physical properties and large critical current density in KCa${}_2$Fe${}_4$As${}_4$F${}_2$ single crystal
• Temperature evolution of quasiparticle dispersion dynamics in semimetallic 1T-TiTe2 via high-resolution angle-resolved photoemission spectroscopy and ultrafast optical pump-probe spectroscopy
• Dirac semimetal PdTe2 temperature-dependent quasiparticle dynamics and electron-phonon coupling
• High Tc superconductivity in CaKFe${}_4$As${}_4$ in absence of nematic fluctuations
• Study of pseudogap and superconducting quasiparticle dynamics in $\mathrm{B}{\mathrm{i}}_2\mathrm{S}{\mathrm{r}}_2\mathrm{CaC}{\mathrm{u}}_2{\mathrm{O}}_{8+\delta }$ by time-resolved optical reflectivity

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• Multiple charge-density-wave gaps in LaSbTe and CeSbTe as revealed by ultrafast spectroscopy
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• Research on topological materials using ultrafast spectroscopy