2 7 M ar 2 01 9 Imaging anisotropic vortex dynamics in FeSe

Irene P. Zhang, 2 Johanna C. Palmstrom, 2 Hilary Noad, 2 Logan Bishop-Van Horn, 3 Yusuke Iguchi, 2 Zheng Cui, 2 John R. Kirtley, Ian R. Fisher, 2, 4 and Kathryn A. Moler 2, 4 Department of Applied Physics, Stanford University, Stanford, CA 94305, USA Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA Department of Physics, Stanford University, Stanford, CA 94305, USA Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305, USA (Dated: March 28, 2019)