Large excitonic effect on van der Waals interaction between two-dimensional semiconductors

Abstract

Electron–hole interaction has an exceptionally large effect on the long-range van der Waals energy between two-dimensional semiconductors.

Nonmonotonous Distance Dependence of van der Waals Screening by a Dielectric Layer

“…The vdWS by dielectric layers of semiconducting or insulating cubic materials were investigated using the Lifshitz theory. The formulas as introduced in the textbook of Parsegian and described in the previous work were applied, , with the temperature T set to 293.15 K. For the optical absorption spectra, density functional theory simulations with the Perdew–Burke–Ernzernhof functional and projector augmented-wave method were performed, , utilizing dense K -point samplings and numerous empty bands. The dielectric functions along the imaginary frequency axis, the key inputs in the Lifshitz theory, were derived from the optical absorption spectra via the Kramers–Kronig relationship (see Figure S1a,b in the Supporting Information for the optical spectra and dielectric functions).…”