Gap in KFe&lt;sub&gt;2&lt;/sub&gt;As&lt;sub&gt;2&lt;/sub&gt; studied by small-angle neutron scattering observations of the magnetic vortex lattice

Kawano-Furukawa, H.; Bowell, C.J.; White, J.S.; Heslop, R.W.; Cameron, A.S.; Forgan, E.M.; Kihou, K.; Lee, C.H.; Iyo, A.; Eisaki, H.; Saito, T.; Fukazawa, H.; Kohori, Y.; Cubitt, R.; Dewhurst, C.D.; Gavilano, J.L.; Zolliker, M.

doi:10.1103/PhysRevB.84.024507

Gap in KFe₂As₂ studied by small-angle neutron scattering observations of the magnetic vortex lattice

Kawano-Furukawa H, Bowell CJ, White JS, Heslop RW, Cameron AS, Forgan EM, Kihou K, Lee CH, Iyo A, Eisaki H, Saito T, Fukazawa H, Kohori Y, Cubitt R, Dewhurst CD, Gavilano JL & Zolliker M

Citation

Kawano-Furukawa, H., Bowell, C. J., White, J. S., Heslop, R. W., Cameron, A. S., Forgan, E. M., … Zolliker, M. (2011). Gap in KFe₂As₂ studied by small-angle neutron scattering observations of the magnetic vortex lattice. Physical Review B, 84(2), 24507 (9 pp.). https://doi.org/10.1103/PhysRevB.84.024507

Persistent URL https://www.dora.lib4ri.ch/psi/islandora/object/psi:14089

By neutron scattering, we have observed a well-ordered magnetic vortex lattice (VL) in KFe₂As₂ single crystals. With the field along the c axis, a nearly isotropic hexagonal VL is formed, with no symmetry transitions up to high fields, indicating a small anisotropy of the superconducting state around this axis. This rules out line nodes parallel to the c axis, and thus d-wave or anisotropic s-wave pairing. However, the strong temperature dependence of the signal at T « T_c shows that extremely small gap values exist; these may arise from nodal lines perpendicular to the c axis.