Impurity scattering rate and coherence factor in vortex core of sign-reversing -wave superconductors

Nagai, Yuki   ; Kato, Yusuke*

We investigate the impurity scattering rates for quasi-particles in vortex cores of sign-reversing -wave superconductors as a probe to detect the internal phase difference of the order parameters. The impurity scattering rates can be detected as a quasiparticle interference effect (QPI) by the scanning tunneling microscopy and spectroscopy (STM/STS) technique. With use of the Born and Kramer-Pesch approximations for Andreev bound states, we show that the sign-reversed forward scatterings are dominant in vortex cores. Owing to the coherence factor in vortex cores of -wave superconductors, the impurity scattering rate of the Andreev bound states has a characteristic distribution on the Fermi surfaces. For comparison, the impurity scattering rates in vortex cores of -wave and -wave superconductors are also discussed.