The role of dynamical screening in correlated materials
14:00 - 15:00
Lund University, Sweden
CFEL (Bldg. 99)
Seminar Room IV, O1.111
A physically motivated approach for studying the electronic structure of strongly correlated materials is
to focus on a subspace of the full Hilbert space containing most of the relevant correlation effects. The
reduction to a limited subspace results in an energy-dependent effective electron-electron interaction U.
It was not until recently an impurity problem with dynamic U could be solved within dynamical meanfield
theory (DMFT) using continuous-time quantum Monte Carlo technique. The energy dependence of
U can have unexpected consequences. As an illustration, we consider La2CuO4, the prototype of hightemperature
superconductor parent compounds. DMFT calculations on undoped La2CuO4 show the
important role of dynamic U: starting from the local density band structure, the insulating state is not
obtained when a static U calculated from first-principles is used. Analysis of U and the DMFT spectral
functions leads to a new insight into the nature of the electronic structure of charge-transfer insulators to
which La2CuO4 belongs.