Extending QEDFT electron-photon exchange-correlation functionals for materials*

Recent advances in optical confinement have granted an active role to light in the task of controlling chemical properties. In the so-called strong-coupling regime, hybrid electron-photon states, or polaritons, emerge and are crucial to understanding changes in chemical processes.^1,2 These experiments have led to a flurry of new theoretical developments to model such new phenomena. Quantum electrodynamical density functional theory (QEDFT) is an extension of electronic DFT to study polaritonic systems.³ As in traditional DFT, the development of more accurate density functional approximations (DFAs) is of paramount importance to render QEDFT useful for chemical applications.^4,5

In this work, we extend the recently developed GA electron-photon exchange-correlation functional⁵ to study condensed matter systems. We analyze how the coupling to a cavity can modify the band structure of simple semiconductors and insulators, comparing our results to other QEDFT DFAs. Finally, we will present an application of our periodic QEDFT implementation to investigate the effects of strong light-matter coupling to systems of catalytic interest, such as molecules adsorbed to surfaces.

References

1. Angew. Chem. Int. Ed., 51.7 (2012): 1592-1596.

2. Science, 354.6309 (2016): aag1992.

3. Phys. Rev. A,  90.1 (2014): 012508

4. Proc. Natl. Acad. Sci., 118.41 (2021): e2110464118

5. Phys. Rev. Lett., 129.14 (2022): 14320