Probing excitons in Al2O3 through Resonant Inelastic X-ray Scattering (Laura Urquiza)
Channel: Francesco Sottile
Date: 2023-12-08

Webinar within the GDR REST and ETSF series, given on 20 October 2023. 

Resonant inelastic X-ray scattering (RIXS) is a powerful technique for studying elementary     
excitations due to its element and orbital specificity, as well as its access to a wide        
range of energies and momenta. The theoretical description of the RIXS double differential     
cross-section is typically carried out using all-electron calculations. Here, we present a     
study of shallow-core excitations at the L-edges of aluminum in α-Al2O3 using a                
pseudopotential plane-wave framework. Since strong excitonic effects have been observed in     
the optical [1] and core [2] absorption spectra of alumina, we perform the calculations        
using the Bethe-Salpeter equation (BSE), which is the state-of-the-art technique for           
describing electron-hole interactions.                                                         
In our work, we address the question of the validity of the pseudopotential approximation      
for RIXS spectra of shallow-core edges. We investigate the limits of the pseudization of       
the wave functions in many-body BSE calculations and the advantages of treating all the        
valence and shallow-core electrons on the same footing.  

1] Marinopoulos et.al, Phys. Rev. B 83 (2011) 195129                                          
[2] Mogi et.al, Materials Transactions, 45 (2004) 2031-2034