%A Yuan-Qiao Li, Tao Zhou %T Impurity effect as a probe for the pairing symmetry of graphene-based superconductors %0 Journal Article %D 2021 %J Front. Phys. %J Frontiers of Physics %@ 2095-0462 %R 10.1007/s11467-021-1056-y %P 43502-${article.jieShuYe} %V 16 %N 4 %U {https://journal.hep.com.cn/fop/EN/10.1007/s11467-021-1056-y %8 2021-08-15 %X

We study theoretically the single impurity effect on graphene-based superconductors. Four different pairing symmetries are discussed. Sharp in-gap resonant peaks are found near the impurity site for the d+id pairing symmetry and the p+ip pairing symmetry when the chemical potential is large. As the chemical potential decreases, the in-gap states are robust for the d + id pairing symmetry while they disappear for the p + ip pairing symmetry. Such in-gap peaks are absent for the fully gapped extended s-wave pairing symmetry and the nodal f-wave pairing symmetry. The existence of the ingap resonant peaks can be explained well based on the sign-reversal of the superconducting gap along different Fermi pockets and by analyzing the denominator of the T-matrix. All of the features may be checked by the experiments, providing a useful probe for the pairing symmetry of graphene-based superconductors.