Cavity Control of Excitons in Two-Dimensional Materials

Nano Letters 19, 3473 - 3479 (2019)

Cavity Control of Excitons in Two-Dimensional Materials

Simone Latini, Enrico Ronca, Umberto de Giovannini, Hannes Hübener, Angel Rubio

We propose a robust and efficient way of controlling the optical spectra of two-dimensional materials and van der Waals heterostructures by quantum cavity embedding. The cavity light-matter coupling leads to the formation of exciton–polaritons, a superposition of photons and excitons. Our first-principles study demonstrates a reordering and mixing of bright and dark excitons spectral features and in the case of a type II van-der-Waals heterostructure an inversion of intra- and interlayer excitonic resonances. We further show that the cavity light-matter coupling strongly depends on the dielectric environment and can be controlled by encapsulating the active two-dimensional (2D) crystal in another dielectric material. Our theoretical calculations are based on a newly developed nonperturbative many-body framework to solve the coupled electron–photon Schrödinger equation in a quantum-electrodynamical extension of the Bethe-Salpeter approach. This approach enables the ab initio simulations of exciton–polariton states and their dispersion from weak to strong cavity light-matter coupling regimes. Our method is then extended to treat van der Waals heterostructures and encapsulated 2D materials using a simplified Mott-Wannier description of the excitons that can be applied to very large systems beyond reach for fully ab initio approaches.

Additional Information

Preprint - 2.56 MB
We are grateful for helpful discussions with Ch. Schäfer, M.Sentef, and M. Ruggenthaler. S.L. acknowledges support from the Alexander von Humboldt foundation. We further acknowledge financial support from the European Research Council (ERC-2015-AdG-694097). The Flatiron Institute is a division of the Simons Foundation.

Related Projects

Related Research Areas