Spectroscopic techniques are an essential tool in probing electronic, optical and structural properties of materials. Besides those techniques, numerical simulations of spectroscopic properties help in the interpretation of the experimental results, and may even guide and motivate new experiments. In this context, we develop theoretical and numerical approaches, as well as computational tools, within the framework of many-body perturbation theory and density functional theory.
Many-body perturbation theory allows to systematically capture correlation effects responsible for emergent collective behaviours in an electronic system. Combining many-body perturbation theory with density-functional theory results in universal, parameter-free numerical approaches that allow one to quantitatively address spectroscopic properties of materials, given the atomic positions as the only input. Indeed, those techniques are nowadays the state-of-the-art to simulate e.g. optical absorption, electron energy loss and photoemission spectra for a broad range of materials.
Notwithstanding this success, active development of those approaches, and the associated computational tools are ongoing:
- to design strategies and efficient numerical algorithms to treat systems with a large number of degrees of freedom
- to capture relevant effects that are not yet included in state-of-the-art approaches (e.g. temperature)
- to describe other spectroscopic properties (e.g real-time, femtosecond spectroscopic techniques) and excitations
Researcher: Myrta Grüning
- Pablo Aguado-Puente, Stephen Fahy, and Myrta Grüning Phys. Rev. Research 2, 043105
- D. Sangalli et al Journal of Physics: Condensed Matter 31 325902 (2019)
- B. Cunningham, M. Grüning, P. Azarhoosh, D. Pashov, M. van Schilfgaarde Phys. Rev. Materials 2 (2018) 034603
- M. Grüning and C. Attaccalite Phys. Rev. B 89, 081102(R)
- Attaccalite, C.; Grüning, M.; Marini, A. Physical Review B 84 (2011) 245110
Theoretical and numerical progress is mainly implemented in Yambo.
The Questaal suite of electronic structure programs.
Main collaborators, doctoral and postdoctoral researchers:
Claudio Attaccalite (CNRS Marseille); Davide Sangalli (CNR-ISM Rome); Mark van Schilfgaarde (NREL - Colorado), Ignacio Alliati