Magnetization-induced symmetry breaking at the surface of ferromagnetic Ni(111)

The exchange-split sp states of Ni(111) are investigated for different magnetization conditions by means of angle-resolved photoelectron spectroscopy with polarized synchrotron radiation. Significant shifts of intensity maxima in both energy and wave vector are found upon reversal of the magnetization. The shifts, not present in demagnetized samples, are unequivocally related to the direction of the magnetization vector and, hence, attributed to the spin-orbit interaction. Symmetry considerations corroborate that the experimental findings are related to magnetization-induced explicit symmetry breaking at fcc(111) surfaces.