Methods for Dynamical Simulations in Advanced Materials

This talk will cover several methods for dynamical simulations of advanced materials, including ultrafast phase transitions. In our first method, Ginzburg-Landau-like order parameters are coupled to each other and to the vector potential of an incoming laser pulse, so that the resulting phase transition is described by time-dependent Ginzburg-Landau theory. This approach is capable of describing one mechanism which is observed experimentally in light-induced superconductivity. A method will be introduced for treating ultrafast phase transitions, such as those involving superconductivity, magnetism, charge density waves, and spin density waves. Results will be presented for a toy model, with the electronic temperature immediately after the laser pulse calculated as a function of the fluence. Finally, we improve on this approach with the addition of an electronic self-energy, which allows for calculations currently not possible with conventional density-functional-based methods.