SKM 2021 – scientific programme

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SYAW: Awards Symposium

SYAW 1: Prize Talks

SYAW 1.3: Prize Talk

Wednesday, September 29, 2021, 14:40–15:10, Audimax 1

Fingerprints of correlation in electronic spectra of materials — •Lucia Reining — LSI, CNRS/CEA/Ecole Polytechnique, Institut Polytechnique de Paris, Palaiseau,France — European Theoretical Spectroscopy Facility — Laureate of the Gentner-Kastler-Prize 2020

Many properties of materials are determined by electronic excitations, which can be observed in spectroscopic experiments, such as absorption or photoemission. However, electronic spectra of a real many-body system are often very different from what an independent-particle picture would suggest. How can theory understand, and how can calculations predict, the wealth of unexpected phenomena that may take place ? Density functional theory and many-body perturbation theory based on Green's functions are powerful approaches to face this problem, and indeed, ab initio calculations often yield reliable band structures. However, electronic excitation spectra contain much more: they may exhibit lifetime broadening, an incoherent background or distinct satellite structures. These features are pure correlation effects that cannot be captured by any independent-particle picture, and they are at the forefront of the capabilities of current first principles approaches. In this talk we will present recent progress in the theoretical description and analysis of correlation effects such as satellites in photoemission and inelastic x-ray scattering spectra, using density functionals [1], Green's functions [2], and close collaboration with experiment, and we will discuss new challenges. [1] e.g., M. Panholzer, M. Gatti, and L. Reining, Phys. Rev. Lett. 120, 166402 (2018). [2] e.g., J.S. Zhou, et al., J. Chem. Phys. 143, 184109 (2015); PNAS 117, 28596 (2020).