Influence of the multiband sign changing superconductivity on the vortex cores and on vortex pinning in the new stoichiometric high Tc CaKFe4As4

A. Fente, W. R. Meier, T. Kong +5

We study the superconducting density of states and vortex lattice of single crystals of CaKFe${}_4$As${}_4$ using a scanning tunneling microscope (STM). This material has a critical te…