Speaker
Description
The influence of the dielectric environment on material properties has been studied theoretically mostly within two different contexts: Within Coulomb engineering one uses electrostatic screening of the longitudinal electromagnetic field to renormalize interactions. In contrast, within cavity material engineering one tries to shape the modes of the enveloping electromagnetic field to produce desired material properties. For these settings we present a unifying gauge consistent description in the form of the constraint random phase approximation extended to the transverse components of the electromagnetic field. Using this formalism we derive the action and Hamiltonian for the Hubbard model in the near-field of surface phonon-polaritons. We compute its phase diagram using DMFT + GW, where we find a shift of the metal-to-insulator transition near the surface. We compare this shift in different gauges.