Non-linear response of solids and nanostructures: A real-time prospective

Psi-k Scientific Highlight https://psi-k.net/download/highlights/Highlight_154.pdfIn recent years many theoretical approaches and computational codes have been developed to study optical response of bulk materials, ranging from many-body perturbation theory to density functional like methods. However the major part of these approaches are limited to the linear optical regime. The few that are formulated in real-time are based on time-dependent density functional theory, an approach where it is di cult to include correlation effects especially for solids. In order to overcome these difficulties some years ago we devised a new real-time computational approach based on dynamical Berry phase plus many-body perturbation theory. This approach is particularly suited to study nonlinear optical properties in crystalline solids and periodic nanostructures. In this highlight we present an introduction to nonlinear optics in solids and how the nonlinear response can be obtained by means of real-time simulations including correlation effects