Ab InitioTreatment of Optical Second Harmonic Generation in NiO

Abstract

In this Letter we develop a new systematic approach to study optical second harmonic generation in NiO, on both the (001) surface and the bulk. NiO is modeled as a doubly embedded cluster on which two highly correlated quantum chemistry methods are applied in order to obtain the wave functions of all the intragap d states and the low lying charge transfer states. The optical gap is calculated and the electric dipole, magnetic dipole, and electric quadrupole contributions to the second order susceptibility tensor are computed for the first time from first principles. Going beyond the electric dipole approximation gives new insight into the experimentally observed spectrum. A method is proposed for monitoring the spin dynamics of the NiO(001) surface.

Optical spin manipulation for minimal magnetic logic operations in metallic three-center magnetic clusters

“…First the highly correlated electronic structure of the system is obtained on a nonrelativistic level with the use of the symmetry-adapted cluster configuration-interaction method ͑SAC-CI͒ of Nakatsuji et al 19 incorporated in the GAUSSIAN 03 package. 20 Then SOC and an external static magnetic field are added by means of time-independent perturbation theory and finally the laser pulse is turned on as a time-dependent perturbation ͑semiclassical model͒; integration over time is done with the fifth order Runge-Kutta method and CashKarp adaptive step size control ͑see previous works [13][14][15] ͒. The expectation values of the various operators are calculated with the reduced-density-matrix formalism in order to determine their spatial localization as well.…”

“…In previous works we have shown the possibility of local all-optical spin switching, i.e., the explicit addressing and local manipulation of the spins of a NiO cluster embedded in a well-defined chemical environment [13][14][15] and two-magneticcenter metallic chains. 16,17 In this paper we extend this idea further by including more magnetic centers so that an alloptical spin transfer as an additional scenario can be realized along with the local spin-switching mechanism, thus leading to an enhanced functionality.…”

Quadratic effects in the nonlinear magneto-optical response of perovskite manganites studied with magnetization-induced second harmonic generation

“…However, in order to confirm the large value of the quadrupole susceptibility, the firstprinciple calculations are necessary in the way it was recently done for NiO. 24 The high value of the quadratic in magnetization term ͑which is the second term in a Taylor expansion and therefore should be much smaller than previous terms͒ is quite intriguing. It can be explained in terms of quantum mechanical perturbation theory.…”

Ab initiosecond-order nonlinear optics in solids: Second-harmonic generation spectroscopy from time-dependent density-functional theory

“…Since its discovery in 1961 5 the importance of SHG has grown, because of its sensitivity to space symmetry, making SHG an extremely versatile tools for studying many kinds of surfaces [6][7][8][9][10] , superlattices 11 and interfaces 10,[12][13][14] . Nowadays this technique is also used for characterizing systems like interfaces of nanocrystals 15 or as a probe for molecular chirality in polymers 16,17 and nanotubes 18 .…”