Visualization of localized perturbations on a (001) surface of the ferromagnetic semimetal EuB6

We performed scanning tunneling microscopy (STM) and spectroscopy on a (001) surface of the ferromagnetic semimetal EuB6. Large-amplitude oscillations emanating from the elastic scattering of electrons by the surface impurities are observed in topography and in differential conductance maps. Fourier transform of the conductance maps embracing these regions indicate a holelike dispersion centered around the (Gamma) over bar point of the two-dimensional Brillouin zone. Using density functional theory slab calculations, we identify a spin-split surface state, which stems from the dangling p(z) orbitals of the apical boron atom. Hybridization with bulk electronic states leads to a resonance enhancement in certain regions around the (Gamma) over bar point, contributing to the remarkably strong real-space response around static (Gamma) over bar point defects, which are observed in STM measurements.