Signature of a collective spin mode in the local tunneling spectra of a d-wave superconductor

We consider the influence of magnetic excitations on the local density of states in the d-wave superconductor. The magnetic susceptibility is calculated within the renormalized (formula presented) model while its influence on the quasiparticle self-energy is considered in the framework of a model proposed by Polkovnikov et al. [Phys. Rev. B 65, 220509 (2002)]. We find the local density of states (LDOS) is spatially modulated, with the associated wave vectors both along (formula presented) and (formula presented) directions and their magnitudes changing as the energy is varied. The calculated LDOS is compared with the recent scanning tunneling microscope data on bismuth-oxide superconductor.