Two characteristic energies in the low-energy magnetic response of the electron-doped high-temperature superconductor Nd(2-x)Ce(x)CuO(4+delta)

Abstract

Neutron scattering for Nd2-xCexCuO4+delta(x approximate to 0.155, T-c=25 K) reveals two distinct magnetic energy scales in the superconducting state: omega(1)approximate to 6.4 meV and omega(2)approximate to 4.5 meV. These magnetic energies agree quantitatively with the B-1g/B-2g and A(1g) features observed in electronic Raman scattering, where the former is believed to indicate the maximum superconducting gap and the origin of the latter has remained unexplained. The data are inconsistent with previous claims of the existence of a magnetic resonance mode near 10 meV, but consistent with a resonance at omega(2) and with the recently established universal ratio of resonance energy to superconducting gap in unconventional superconductors.[G. Yu et al., Nat. Phys. 5, 873 (2009)]. © 2010, American Physical Society