DMFT-QE Symposium: September 16

Talk 1:

The noncausality problem in non-local extensions of DMFT and implications for high-energy satellites in the spectral function

Steffen Backes, RIKEN Interdisciplinary Theoretical and Mathematical Sciences Program

In the last decade non-local extensions of the highly successful dynamical mean-field theory (DMFT) have become state of the art in order to access various phenomena that arise from nonlocal correlations. Though, it was realized that the success of these methods can be hampered by the emergence of noncausal features in the effective or observable quantities involved. Here we will discuss a modified approach of extending the local DMFT equations to nonlocal correlations, which preserves causality and has a physically intuitive interpretation. We will show benchmark calculations on model systems, and apply the method to representative transition metal oxides, in order to analyze the physical origin of their high energy spectral features. We find evidence that these systems exhibit both Hubbard and plasmonic satellites at very similar energetic positions.

Talk 2:

Semi-local exchange and dynamical mean-field theory approach to the electronic structure of rare-earth semiconductors

Anna Galler, Institute of Theoretical and Computational Physics, TU Graz

Rare-earth semiconductors, including rare-earth mononitrides and fluorosulfides, hold significant potential for optics and spintronics applications. However, accurately modelling their electronic structure is challenging due to the coexistence of wide conduction and valence bands with Mott-localized 4f states. In this talk, I will introduce a computational approach that combines dynamical mean-field theory (DMFT) to handle the localized 4f shells with a semi-local exchange-correlation potential to better describe band gaps. I employ this method to compute the electronic structure and optical response of several rare-earth semiconductors and show that we can reliably predict their electronic structure and optical properties.

[1] Galler and Pourovskii, New J. Phys. 24, 043039 (2022)

[2] Galler, Boust, Demourgues, Biermann and Pourovskii, PRB 103, L241105 (2021)

For the full DMFT-QE Symposium go here.