A distinct bosonic mode in an electron-doped high-transition-temperature superconductor

Abstract

Despite recent advances in understanding high-transition-temperature (high-T c) superconductors, there is no consensus on the origin of the superconducting 'glue': that is, the mediator that binds electrons into superconducting pairs. The main contenders are lattice vibrations (phonons) and spin-excitations with the additional possibility of pairing without mediators. In conventional superconductors, phonon-mediated pairing was unequivocally established by data from tunnelling experiments. Proponents of phonons as the high-T c glue were therefore encouraged by the recent scanning tunnelling microscopy experiments on hole-doped Bi2Sr2CaCu2O8-delta (BSCCO) that reveal an oxygen lattice vibrational mode whose energy is anticorrelated with the superconducting gap energy scale. Here we report high-resolution scanning tunnelling microscopy measurements of the electron-doped high-T c superconductor Pr0.88LaCe0.12CuO4 (PLCCO) (T c = 24 K) that reveal a bosonic excitation (mode) at energies of 10.5 plus/minus 2.5 meV. This energy is consistent with both spin-excitations in PLCCO measured by inelastic neutron scattering (resonance mode) and a low-energy acoustic phonon mode, but differs substantially from the oxygen vibrational mode identified in BSCCO. Our analysis of the variation of the local mode energy and intensity with the local gap energy scale indicates an electronic origin of the mode consistent with spin-excitations rather than phonons.

References in corpus (6)

• Interplay of electron-lattice interactions and superconductivity in Bi2Sr2CaCu2O8+d
• Resonance in the electron-doped high-Tc superconductor Pr0.88LaCe0.12CuO(4-delta)
• Resonance in Optimally Electron-Doped Superconductor Nd${}_{1.85}$Ce${}_{0.15}$CuO${}_{4-\delta }$
• Weak coupling Bardeen-Cooper-Schrieffer suerconductivity in the Electron-Doped Cuprate Superconductors
• Role of Inelastic Tunneling through the Barrier in Scanning Tunneling Microscope Experiments on Cuprates
• Universal quasiparticle decoherence in hole- and electron-doped high-Tc cuprates

Cited by in corpus (12)

• Electronic Origin of the Inhomogeneous Pairing Interaction in the High-Tc Superconductor Bi2Sr2CaCu2O8+d
• Coexistence of competing orders with two energy gaps in real and momentum space in high-Tc superconductor Bi2Sr2-xLaxCuO6+delta
• Angle-resolved photoemission spectroscopy of electron-doped cuprate superconductors: Isotropic electron-phonon coupling
• Weak coupling Bardeen-Cooper-Schrieffer suerconductivity in the Electron-Doped Cuprate Superconductors
• Fidelity and superconductivity in two-dimensional t-J models
• Multiple bosonic mode coupling in the charge dynamics of the electron-doped superconductor (Pr${}_{2-x}$Ce${}_x$)CuO${}_4$
• Observation of vortices and hidden pseudogap from scanning tunneling spectroscopic studies of electron-doped cuprate superconductor $S{r}_{0.9}L{a}_{0.1}Cu{O}_2$
• Excitation of a bosonic mode by electron tunneling into a cuprate superconductor
• Effects of Strong Correlations and Disorder in d-Wave Superconductors
• Effect of spin excitations on the property of quasiparticles in electron-doped cuprates
• Signatures of superconducting gap inhomogeneities in optical properties
• Superconductors described with CSM.(a new paper, 2008-10-16)