LAUSR

High critical temperature superconductivity often occurs in systems where an antiferromagnetic order is brought near $T=0$ K by slightly modifying pressure or doping. ${\mathrm{CaKFe}}_{4}{\mathrm{As}}_{4}$ is a superconducting, stoichiometric iron-pnictide compound showing optimal superconducting critical temperature with ${T}_{c}$ as large as 35 K. Doping with Ni induces a decrease in ${T}_{c}$ and the onset of spin-vortex crystal (SVC) antiferromagnetic order, which consists of spins pointing inwards to or outwards from alternating As sites on the diagonals of the in-plane square Fe lattice. Here we study the band structure of $\mathrm{CaK}{({\mathrm{Fe}}_{0.95}{\mathrm{Ni}}_{0.05})}_{4}{\mathrm{As}}_{4}$ $({T}_{c}=10 \mathrm{K},$ ${T}_{SVC}=50 \mathrm{K})$ using quasiparticle interference with a scanning tunneling microscope and show how the SVC modifies the band structure and induces a fourfold superconducting gap anisotropy.