Hedgehog spin-vortex crystal stabilized in a hole-doped iron-based superconductor

William R. Meier, Qing Ping Ding, Andreas Kreyssig, Sergey L. Bud'Ko, Aashish Sapkota, Karunakar Kothapalli, Vladislav Borisov, Roser Valentí, Cristian D. Batista, Peter P. Orth, Rafael M. Fernandes, Alan I. Goldman, Yuji Furukawa, Anna E. Böhmer, Paul C. Canfield