Regensburg 2025 – scientific programme
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O: Fachverband Oberflächenphysik
O 11: Electronic Structure of Surfaces: Spectroscopy, Surface States I
O 11.5: Talk
Monday, March 17, 2025, 16:00–16:15, H4
Computationally Efficient First-Principles Treatment of Scattering States in Photoemission: A Pseudo-potential Approach — •Gian Parusa1,2,3 and Michael Schüler1,2,3 — 1PSI Center for Scientific Computing, Theory and Data, 5232 Villigen PSI, Switzerland — 2National Centre for Computational Design and Discovery of Novel Materials (MARVEL), Paul Scherrer Institute, 5232 Villigen PSI, Switzerland — 3Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
The calculation of photoemission matrix elements requires the consideration of several key factors, including Bloch states, light-matter coupling, and scattering states. The evaluation of scattering states in solids from first-principles, particularly within a plane-wave basis, is computationally demanding due to the large number of plane waves required at high energies. A well-established strategy for reducing the computational cost in the treatment of valence states involves the use of pseudo-potentials. In this work, we extend the concept of optimized norm-conserving pseudo-potentials to scattering states, utilizing a non-local Vanderbilt projector to restore the wave function properties at a specified target energy. This approach is applied to scattering states, specifically for energies above 1 Rydberg. The method is validated by simulating the photoemission spectrum of graphene and hexagonal boron nitride (h-BN) with the results compared to all-electron calculations, demonstrating both the accuracy and computational efficiency of the proposed technique.
Keywords: photoemission; scattering states; pseudo-potentials; graphene; hexagonal boron nitride (h-BN)