Gauge invariance of light-matter interactions in first-principle tight-binding models
Gauge invariance of light-matter interactions in first-principle tight-binding models
We study the different ways of introducing light-matter interaction in first-principle tight-binding (TB) models. The standard way of describing optical properties is the velocity gauge, defined by linear coupling to the vector potential. In finite systems a transformation to represent the electromagnetic radiation by the electric field instead is possible, …