Analysis of Resonant Soft X-ray Reflectivity of Anisotropic Layered Materials

Luca Pasquali (1, 2, 3) , Nicola Mahne (2) , Angelo Giglia (2) , Adriano Verna (4) , Lorenzo Sponza (5) , Raffaella Capelli (1, 2, 3) , Matteo Bonfatti (1) , Francesco Mezzadri (1) , Emanuele Galligani (1) , Stefano Nannarone (2)

1 UNIMORE - Università degli Studi di Modena e Reggio Emilia = University of Modena and Reggio Emilia
2 IOM - CNR Istituto Officina dei Materiali
3 UJ - University of Johannesburg [South Africa]
4 ROMA TRE - Università degli Studi Roma Tre = Roma Tre University
5 Laboratoire d'étude des microstructures - LEM, UMR 104, CNRS-ONERA, Université Paris-Saclay

We present here a method for the quantitative prediction of the spectroscopic specular reflectivity line-shape in anisotropic layered media. The method is based on a 4 × 4 matrix formalism and on the simulation from the first principles (through density functional theory—DFT) of the anisotropic absorption cross-section. The approach was used to simulate the reflectivity at the oxygen K-edge of a 3,4,9,10-perylene-tetracarboxylic dianhydride (PTCDA) thin film on Au(111). The effect of film thickness, orientation of the molecules, and grazing incidence angle were considered. The simulation results were compared to the experiment, permitting us to derive information on the film geometry, thickness, and morphology, as well as the electronic structure.

Mots clés: Soft X-ray reflectivity; Anisotropic optical properties; Organic thin films

Domaines: Sciences de l'ingénieur [physics]; Physique [physics]; Chimie

Luca Pasquali, Nicola Mahne, Angelo Giglia, Adriano Verna, Lorenzo Sponza, et al.. Analysis of Resonant Soft X-ray Reflectivity of Anisotropic Layered Materials. Surfaces and Interfaces, 2021, 4 (1), pp.18 - 30. ⟨10.3390/surfaces4010004⟩. ⟨hal-03132778⟩