Pair-breaking scattering interference as a mechanism for superconducting gap modulation

Abstract

We propose the ``pair-breaking scattering interference" as a general source of coherence peak modulations in superconductors. Assuming this mechanism, we present a simple physical picture for the coherence peak modulations in overdoped cuprate Bi${}_2$Sr${}_2$Ca${}_2$Cu${}_3$O${}_{10+\hat{I}´}$ (Bi-2223), ferromagnetic iron pnictide EuRbFe${}_4$As${}_4$ (Eu-1144), and kagome metals $A$V${}_3$Sb${}_5$ ($A=$ K, Rb, and Cs). Specifically, we explain the wavevectors, the particle-hole symmetry, and the dependence on the internal or external Zeeman-field of the coherence peak modulations. This work is intended as a cautious reminder to the scientific community when asserting the existence of a pair density wave phenomenon in the absence of tunneling conductance modulations in the normal state.

6+6 pages, 3+2 figures