Speaker: Lucas Wagner, UIUC
Time: February 9, 2016, 1:00 - 2:00
First principles calculations, in which materials are simulated using only fundamental constants, are a powerful way to study electronic structure of materials. However, the first principles Hamiltonian exists in a very large Hilbert space, and until recently the only viable method of performing first principles calculations was by using density functional theory(DFT). While DFT has been very successful, its current formulations often do not provide an accurate description of strongly correlated systems.
In recent years, it has become possible to use approximate but very accurate quantum Monte Carlo techniques on first principles Hamiltonians that apply to strongly correlated systems. These techniques work directly with the many-body wave function and offer much higher accuracy than current density functionals, as well as direct insight into electron correlation effects. I’ll show some progress in using these techniques to study the cuprate materials that have high-Tc superconductivity. We find that the ground state of a hole in the cuprates is reminiscent of a spin polaron, which has implications for the origin of superconductivity in these materials.