Selective coupling of coherent optical phonons in YBa${}_2$Cu${}_3$O${}_{7-\delta }$ with electronic transitions

Abstract

We investigate coherent lattice dynamics in optimally doped YBa${}_2$Cu${}_3$O${}_{7-\delta }$ driven by ultrashort ($\sim$ 12 fs) near infrared (NIR) and near ultraviolet (NUV) pulses. Transient reflectivity experiments, performed at room temperature and under moderate ($<$0.1 mJ/cm${}^2$) excitation fluence, reveal $A_g$-symmetry phonon modes related to the O(2,3) bending in the CuO${}_2$ planes and to the apical O(4) stretching at frequencies between 10 and 15 THz, in addition to the previously reported Ba and Cu(2) vibrations at 3.5 and 4.5 THz. The relative coherent phonon amplitudes are in stark contrast to the relative phonon intensities in the spontaneous Raman scattering spectrum excited at the same wavelength. This contrast indicates mode-dependent contributions of the Raman and non-Raman mechanisms to the coherent phonon generation. We show that the particularly intense coherent Cu(2) phonon, together with its initial phase, supports its generation predominately via a displacive mechanism, possibly involving the charge transfer within the CuO${}_2$ planes. The small amplitude of the coherent out-of-phase O(2,3) bending mode at 10 THz also suggests the involvement of non-Raman generation mechanism. The generation of the other coherent phonons can in principle be explained within the framework of Raman mechanism. When the pump light has the polarization component perpendicular to the CuO${}_2$ plane, the coherent O(4) mode at 15 THz is strongly enhanced compared to the in-plane excitation, corresponding to the large polarizability component associated with the hopping between the apical and the chain oxygens, O(4) and O(1).

arXiv comment16 pages, 13 figures including Appendices

References in corpus (35)

• Optically enhanced coherent transport in YBa2Cu3O6.5 by ultrafast redistribution of interlayer coupling
• Electron-phonon coupling reflecting dynamic charge inhomogeneity in copper-oxide superconductors
• Quasiparticle relaxation dynamics in superconductors with different gap structures: theory and experiments on YBa_{2}Cu_{3}O_{7-δ}
• Phase-sensitive Evidence for d-wave Pairing Symmetry in Electron-doped Cuprate Superconductors
• An unusual isotope effect in a high-transition-temperature superconductor
• The superconducting gap Δ_{c}, the pseudogap Δ_{p} and pair fluctuations above Tc in overdoped YCaBaCuO from femtosecond time-domain spectroscopy
• Tracking Cooper Pairs in a Cuprate Superconductor by Ultrafast Angle-Resolved Photoemission
• Disentangling the electronic and phononic glue in a high-Tc superconductor
• Magnetic neutron scattering in hole doped cuprate superconductors
• Electron-Phonon Coupling in High-Temperature Cuprate Superconductors Determined from Electron Relaxation Rates
• Rapid change of superconductivity and electron-phonon coupling through 19% doping in Bi2212
• Femtosecond Quasiparticle and Phonon Dynamics in Superconducting YBa2Cu3O7 Studied by Wideband Terahertz Spectroscopy
• Controlled vaporization of the superconducting condensate in cuprate superconductors sheds light on the pairing boson
• Charge transfer fluctuation, $d-$wave superconductivity, and the $B_{1g}$ Raman phonon in the Cuprates: A detailed analysis
• Snapshots of the retarded interaction of charge carriers with ultrafast fluctuations in cuprates
• Direct Role of Structural Dynamics in Electron-Lattice Coupling of Superconducting Cuprates
• Pump frequency resonances for light-induced incipient superconductivity in YBa${}_2$Cu${}_3$O${}_{6.5}$
• A new collective mode in YBCO observed by time-domain reflectometry
• Coherent Modulation of the YBa2Cu3O6+x Atomic Structure by Displacive Stimulated Ionic Raman Scattering
• Physical origin of the buckling in CuO${}_2$: Electron-phonon coupling and Raman spectra
• Incommensurate phonon anomaly and the nature of charge density waves in cuprates
• Enhanced electron-phonon coupling for charge-density-wave formation in La${}_{1.8-x}$Eu${}_{0.2}$Sr${}_x$CuO${}_{4+\delta }$
• Distinct charge and spin gaps in underdoped YBa2Cu3O7-x
• Photoinduced melting of superconductivity in the high-Tc superconductor La2-xSrxCuO4 probed by time-resolved optical and THz techniques
• Dynamics of correlation-frozen antinodal quasiparticles in superconducting cuprates
• Charge Order Lock-in by Electron-Phonon Coupling in La${}_{1.675}$Eu${}_{0.2}$Sr${}_{0.125}$CuO${}_4$
• Localised vibrations in superconducting YBCO revealed by ultra-fast optical coherent spectroscopy
• Electron-Phonon-Driven Three-Dimensional Metallicity in an Insulating Cuprate
• A study of photoexcited carrier relaxation in YBa_2Cu_3O_(7-d) by picosecond resonant Raman spectroscopy
• Probing the electron-phonon interaction in correlated systems with coherent lattice fluctuation spectroscopy
• Emergent Charge Order from Correlated Electron-Phonon Physics in Cuprates
• Clocking the Onset of Bilayer Coherence in a High-${\mathrm{T}}_{\mathrm{C}}$ Cuprate
• Probing the Lattice Anharmonicity of Superconducting YBa${}_2$Cu${}_3$O${}_{7-\delta }$ Via Phonon Harmonics
• Relaxation timescales and electron-phonon coupling in optically-pumped YBa${}_2$Cu${}_3$O${}_{6+x}$ revealed by time-resolved Raman scattering
• Ultrafast asymmetric Rosen-Zener-like coherent phonon responses observed in silicon

Cited by in corpus (1)

• Real-space d-wave superconductivity from weak attraction