Spatial modulation of unitary impurity-induced resonances in superconducting CeCoIn5

Abstract

Motivated by recent experimental progress in high-resolution scanning tunneling microscopy (STM) techniques, we propose to investigate the local quasiparticle density of states around a unitary impurity in the heavy fermion superconductor CeCoIn$_{5}$. Based on the T-matrix approach we obtain a sharp nearly zero-energy resonance state (ZERS) in the strong impurity potential scattering localized around the impurity, and find qualitative differences in the spatial pattern of the tunneling conductance modulated by the nodal structure of the superconducting gap. These unique features may be used as a probe of the superconducting gap symmetry and in combination with the further STM measurements, may help to confirm the $d_{x^{2}-y^{2}}$ pairing in CeCoIn$_{5}$ at ambient pressure.