Protected surface state in stepped Fe (0 18 1)

Abstract

Carbon (C) surface segregation from bulk stabilizes the Fe(0 18 1) vicinal surface by forming a c(3 $$\sqrt{2}$$ 2 × $$\sqrt{2}$$ 2 reconstruction with C zig-zag chains oriented at 45° with respect to the iron surface steps. The iron surface electronic states as measured by high resolution ARPES at normal emission with polarized synchrotron radiation split in two peaks that follow distinct energy dispersion curves. One peak follows the dispersion of the carbon superstructure and is photoexcited only when the polarization vector is parallel to the steps, the second peak disperses similarly to the pristine Fe(0 0 1) surface. Such surface electronic structure is robust as it persists even after coating with an Ag overlayer. The robustness of this surface electronic structure and its similarity with that of the clean Fe(0 0 1) surface make this system of interest for magnetic and spintronic properties such as magneto tunnel junctions based on Fe/MgO interface.