Magnetic Dynamics in Underdoped YBCO: Direct Observation of a Superconducting Gap

Abstract

Polarized and unpolarized triple-axis spectrometry has been used to study an underdoped YBa_2Cu3O6.6. Our results indicate that spin excitations in the superconducting state are essentially the same as those in the fully doped material except that the unusual 41 meV resonance is observed at 34.8 meV. The normal state spin excitations are characterized by a weakly energy-dependent continuum whose temperature dependence shows the clear signature of a superconducting gap at Tc. The enhancement at the resonance is accompanied by a suppression of magnetic fluctuations at both higher and lower energies.

12 pages, 4 Postscript figures, Physical Review Letters, to be published

Cited by in corpus (70)

• Angle-resolved photoemission spectroscopy of the cuprate superconductors
• The pseudogap in high-temperature superconductors: an experimental survey
• Spin-Gap Proximity Effect Mechanism of High Temperature Superconductivity
• Neutron Scattering from Magnetic Excitations in Bi_2 Sr_2 Ca_2 O_8+delta
• A Survey of the Van Hove Scenario for High-T_c Superconductivity With Special Emphasis on Pseudogaps and Striped Phases
• Electronic Spectra and Their Relation to the (pi,pi) Collective Mode in High-Tc Superconductors
• The effect of collective spin-1 excitations on electronic spectra in high-Tc superconductors
• Evolution of the resonance and incommensurate spin fluctuations in superconducting YBa${}_2$Cu${}_3$O${}_{6+x}$
• The Magnetic Excitation Spectrum and Thermodynamics of High-$T_c$ Superconductors
• Superconducting Vortex with Antiferromagnetic Core
• Evidence for an energy scale for quasiparticle dispersion in Bi_2Sr_2CaCu_2O_8
• SO(5) Theory of Antiferromagnetism and Superconductivity
• Theory of Superconductivity in Strongly Correlated Electron Systems
• Incommensurate Magnetic Fluctuations in YBa2Cu3O6.6
• Spin Susceptibility in Underdoped $\mathbf{YB}{\mathbf{a}}_2\mathbf{C}{\mathbf{u}}_3{\mathbf{O}}_{6+\mathbf{x}}$
• The connection between superconducting phase correlations and spin excitations in YBa${}_2$Cu${}_3$O${}_{6.6}$: A magnetic field study
• Slave Boson Approach to The Neutron Scattering in YBCO Superconductors
• Hidden magnetic excitation in the pseudogap phase of a model cuprate superconductor
• The resonance peak in cuprate superconductors
• Effect of the magnetic resonance on the electronic spectra of high Tc superconductors
• The Hubbard model within the equations of motion approach
• High energy spin excitations in YBa_2 Cu_3 O_{6.5}
• Renormalized mean-field theory of the neutron scattering in cuprate superconductors
• Magnetic excitations and their anisotropy in YBCO: slave-boson mean-field analysis of bilayer t-J model
• Electron Dynamics in Nd${}_{1.85}$Ce${}_{.15}$CuO${}_{4+\delta }$: Evidence for the Pseudogap State and Unconventional c-axis Response
• Effect of Nonmagnetic Impurities on the Magnetic Resonance Peak in YBa2Cu3O7
• Observation of Magnetic Moments in the Superconducting State of YBa${}_2$Cu${}_3$O${}_{6.6}$
• Spin dynamics of stripes
• Magnetic Order in YBa${}_2$Cu${}_3$O${}_{6+x}$ Superconductors
• An SO(5) model of p-wave superconductivity and ferromagnetism
• Linear dependence of peak width in $χ(\bq, ω)$ vs T_c for YBCO superconductors
• Pi excitation of the t-J model
• Disappearance of static magnetic order and evolution of spin fluctuations in Fe${}_{1+\delta }$Se${}_x$Te${}_{1-x}$
• Mean-Field Description of Phase String Effect in the $t-J$ Model
• Finite-Size Studies on the SO(5) Symmetry of the Hubbard Model
• Neutron scattering search for static magnetism in oxygen ordered YBa2Cu3O6.5
• Charge stripes and spin correlations in copper-oxide superconductors
• The resonance peak in the electron-doped cuprate superconductors
• On Measuring Condensate Fraction in Superconductors
• Stripes, Pseudogaps, and Van Hove Nesting in the Three-band tJ Model
• Shifting of the magnetic resonance peak to lower energy in the superconducting state of underdoped YBa_2Cu_3O_{6.8}
• Fourier-Transformed Local Density of States and Tunneling into a $D$-Wave Superconductor with Bosonic Modes
• Developments in the negative-U modelling of the cuprate HTSC systems
• Influence of higher d-wave gap harmonics on the dynamical magnetic susceptibility of high-temperature superconductors
• Global Phase Diagram of the High Tc Cuprates
• Through a Lattice Darkly -- Shedding Light on Electron-Phonon Coupling in the High T${}_c$ Cuprates
• Pairing and Phase Coherence in High Temperature Superconductors
• Impurity effects on the spin excitation spectra in a d-wave superconductor
• From Ising resonant fluctuations to static uniaxial order in antiferromagnetic and weakly superconducting CeCo(In${}_{1-x}$Hg${}_x$)${}_5$ ($x$=0.01)
• Absolute measurements of the high-frequency magnetic dynamics in high-Tc superconductors
• Search for the πResonance in Two Particle Tunneling Experiments of YBCO Superconductors
• Dynamical spin susceptibility and the resonance peak in the pseudogap region of the underdoped cuprate superconductors
• Theory of doped Mott insulators: duality between pairing and magnetism
• Stripes, pseudogaps, and SO(6) in the cuprate superconductors
• Incommensurate spin fluctuations in the two-dimensional t-t'-U model
• Spin-roton excitations in the cuprate superconductors
• A critical examination of the spin dynamics in high-$T_C$ cuprates
• Neutron Scattering Studies of the Magnetic Fluctuations in YBa_2Cu_3O_{7-δ}
• Origin of Kinks in Energy Dispersion of Strongly Correlated Matter
• Doping Dependence of the Magnetic Resonance Peak in YBa_2 Cu_3 O_{6+x}
• Quantum Ginzburg-Landau theory of doped Mott insulators
• Spin susceptibility and the pi-excitation in underdoped cuprates
• A model for the neutron resonance in HgBa${}_2$CuO${}_{4+\delta }$
• Crossover from Fermi Arc to Full Fermi Surface
• Pseudogap and incommensurate magnetic fluctuations in YBa_2Cu_3O_{6. 6}
• Thermal Hall Effect and Neutral Spinons in a Doped Mott Insulator
• Convergence of energy-dependent incommensurate antiferromagnetic neutron scattering peaks to commensurate resonance in underdoped bilayer cuprates
• The SO(5) theory of high T_c superconductivity
• Identifying Collective Modes via Impurities in the Cuprate Superconductors
• Superconductivity and spin triplet collective mode in the t-J model close to antiferromagnetic instability