Dielectric embedding GW: An accurate and efficient approach for molecule-substrate interfaces

Many nanoscale energy-conversion processes take place at heterogeneous molecule-substrate interfaces. An accurate characterization of the quasiparticle energy level alignment at the interface is central to understanding the interfacial charge dynamics. Although the first-principles GW approach is considered state-of-the-art in computing quasiparticle properties of molecular and extended systems, its routine application to large interface systems has been limited by the relatively high computational cost. In this talk, we present a newly developed dielectric embedding GW approach designed specifically for heterogeneous molecule-substrate interfaces. The idea is to confine expensive GW self-energy calculations within small simulation cells that only consist of either the adsorbate or the substrate, while accurately accounting for the dielectric effect of the other via the inclusion of its Kohn-Sham polarizability. Using a few prototypical molecule-metal and molecule-semiconductor interfaces, we discuss the strengths and limitations of this approach by comparing our approach with direct GW and other related methods.