Evidence for exclusion of the possibility of $d$-wave superconducting-gap symmetry in Ba-doped KFe$_2$As$_2$
cond-mat.supr-con
/ Authors
Y. Ota, K. Okazaki, Y. Kotani, T. Shimojima, W. Malaeb, S. Watanabe, C. -T. Chen, K. Kihou, C. H. Lee, A. Iyo
and 5 more authors
/ Abstract
We have investigated the superconducting(SC)-gap anisotropy for several Ba-doped KFe$_2$As$_2$ samples using laser-based angle-resolved photoemission spectroscopy. We show that the SC-gap anisotropy and node positions drastically change with a small amount of Ba doping. Our results totally exclude a possibility of $d$-wave symmetry and strongly suggest that both spin and orbital fluctuations are important for the paring interaction in the Ba-doped K122.