Efficient GW calculations of covalently bonded interfaces from generalized substrate screening

An accurate description of the quasiparticle electronic structure at heterogeneous molecule-substrate interfaces is key to the understanding of interfacial charge transfer dynamics. It is by far common knowledge that many-body perturbation theory, such as the GW formalism, is required to achieve accuracy. However, direct GW calculations of large-scale interfaces are computationally expensive. The substrate screening approach effectively reduces the computational cost for weakly coupled interfaces with negligible orbital hybridization, by taking advantage of the additivity of the non-interacting polarizability of the interface. Here, we introduce a generalized substrate screening approach, extending this idea to covalently bonded interfaces. The key is to properly passivate the building blocks of the interface and realize that the contribution of the orbital hybridization to the non-interacting polarizability converges faster than that of each building block. We demonstrate our approach with an experimentally well-studied interface, the benzene dithiol adsorbed on Au(111).