Electron-phonon interactions beyond DFT (hybrids, Koopmans, and GW) and their application to resonant Raman

Electron-phonon interactions play a central role in determining a wide range of material properties, from charge transport to optical and vibrational responses such as the Raman spectrum. Accurately describing these interactions is crucial for understanding and predicting material behavior under realistic conditions. However, conventional density-functional theory (DFT) often falls short in describing electronic structures and excited states with sufficient accuracy, leading to limitations in the computed electron-phonon coupling and related properties. In this work, we explore more advanced approaches based on hybrid functionals to enhance the description of electron-phonon interactions and their impact on the resonant Raman response. We extend our previously proposed framework [1] for calculating electron-phonon matrix elements using finite differences to two-dimensional systems. By combining it with Wannier interpolation techniques, we achieve an accurate and efficient description of Raman intensities in the resonant regime [2]. We demonstrate a notably improved agreement of computed intensities for graphene and other prototypical monolayer systems.

[1] A. Poliukhin, N. Colonna, F. Libbi, S. Poncé, and N. Marzari, submitted to npj Computational Materials (2025)

[2] J. Huang, R. Liu, Y. Zhang, N. T. Hung, H. Guo, R. Saito, T. Yang, arXIv, 2505.1004 (2025)