Nonlinear magneto-optics of freestanding Fe monolayers from first principles

The nonlinear magneto-optical Ken-effect (NO-LIMOKE) is determined for free standing Fe monolayers with several in-plane structures from first principl es. Based on the theory of nonlinear magneto-optics by Hubner and Bennemann [1] we calculate the nonlinear susceptibilities of the monolayers using th e ab initio FLAPW-method WIEN95 with the additional implementation of spin- orbit coupling and the calculation of the dipole transition matrix elements appropriate for freestanding monolayers. We present results for the spectr al dependence of the nonlinear susceptibility tensor elements and the resul ting intensities and Ken angles. Special emphasis is put on the effects of structural changes, such as the variation of the lattice constant and diffe rent surface orientations. The influence of spin-orbit coupling on the tens or elements for different magnetization directions is presented. Also, the azimuthal dependence of the intensities generated by several low-index surf aces is given, showing the pronounced sensitivity of second-harmonic genera tion to lateral structural changes and magnetic properties even in the mono layer range.