SKM 2023 – wissenschaftliches Programm
DY 44.2: Poster
Donnerstag, 30. März 2023, 13:00–16:00, P1
Finite-temperature absorption spectrum of Al2O3 from first principles — •Angela F. Harper1, Bartomeu Monserrat2, and Andrew J. Morris3 — 1Fritz Haber Institute of the Max Planck Society, Berlin, Germany — 2University of Cambridge, UK — 3University of Birmingham, UK
Advancing the next generation of materials for solid-state devices requires an understanding of their underlying electronic structure. One such material is alumina (Al2O3), which is used to enhance performance in electronic devices from Li-ion batteries to perovskite solar cells and field effect transistors. By including phonon-assisted transitions within plane-wave DFT methods for calculating the X-ray absorption spectrum (XAS) we obtain the Al K-edge XAS at 300 K for two crystalline Al2O3 phases. The 300 K XAS reproduces the pre-edge peak for α-Al2O3, which is not visible at the static-lattice level of approximation. The 300 K XAS for γ-Al2O3 correctly describes two out of the three experimental peaks. We show that the second peak arises from 1s to mixed s-p transitions and is absent in the 0 K XAS. The method presented here is generalizable to any element and absorption edge, and is a feasible way to calculate finite temperature spectroscopy for any crystalline material.