Parity of the Pairing Bosons in a High-Temperature Superconductor

Borisenko, S. V.; Kordyuk, A. A.; Koitzsch, A.; Fink, J.; Geck, J.; Zabolotnyy, V.; Knupfer, M.; Buechner, B.; Berger, H.; Falub, M.; Shi, M.; Krempasky, J.; Patthey, L.

Parity of the Pairing Bosons in a High-Temperature Superconductor

Authors

Description

We report the observation of a novel effect in the bilayer Pb-Bi2212 high-TC superconductor by means of angle-resolved photoemission with circularly polarized excitation. Different scattering rates, determined as a function of energy separately for the bonding and antibonding copper-oxygen bands, strongly imply that the dominating scattering channel is odd with respect to layer exchange within a bilayer. This is inconsistent with a phonon-mediated scattering and favours the participation of the odd collective spin excitations in the scattering mechanism in near-nodal regions of the k-space, suggesting a magnetic nature of the pairing mediator.
5 RevTex pages, 4 eps figures