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Main Authors: Nozaki, Misa, Krüger, Peter
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2402.17199
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author Nozaki, Misa
Krüger, Peter
author_facet Nozaki, Misa
Krüger, Peter
contents A versatile method for angle-resolved photoemission spectra (ARPES) calculations is reported within the one-step model of photoemission. The initial states are obtained from a repeated-slab calculation using the projector-augmented wave (PAW) method. ARPES final states are constructed by matching the repeated-slab eigenstates of positive energy with free electron states that satisfy the time-reversed low-energy electron diffraction boundary conditions. Nonphysical solutions of the matching equations, which do not respect the flux conservation, are discarded. The method is applied to surface-normal photoemission from graphene as a function of photon energy from threshold up to 100 eV. The results are compared with independently performed multiple scattering calculations and very good agreement is obtained, provided that the photoemission matrix elements are computed with all-electron waves reconstructed from the PAW pseudo-waves. However, if the pseudo-waves are used directly, the relative intensity between $σ$- and $π$-band emission is wrong by an order of magnitude. The graphene ARPES intensity has a strong photon energy dependence including resonances. The normal emission spectrum from the $π$-band shows a hitherto unreported, sharp resonance at a photon energy of 31 eV. The resonance is due to a 2$D$ interband transitions and highlights the importance of matrix element effects beyond the final state plane-wave approximation.
format Preprint
id arxiv_https___arxiv_org_abs_2402_17199
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle A computational method for angle-resolved photoemission spectra from repeated-slab band structure calculations
Nozaki, Misa
Krüger, Peter
Materials Science
A versatile method for angle-resolved photoemission spectra (ARPES) calculations is reported within the one-step model of photoemission. The initial states are obtained from a repeated-slab calculation using the projector-augmented wave (PAW) method. ARPES final states are constructed by matching the repeated-slab eigenstates of positive energy with free electron states that satisfy the time-reversed low-energy electron diffraction boundary conditions. Nonphysical solutions of the matching equations, which do not respect the flux conservation, are discarded. The method is applied to surface-normal photoemission from graphene as a function of photon energy from threshold up to 100 eV. The results are compared with independently performed multiple scattering calculations and very good agreement is obtained, provided that the photoemission matrix elements are computed with all-electron waves reconstructed from the PAW pseudo-waves. However, if the pseudo-waves are used directly, the relative intensity between $σ$- and $π$-band emission is wrong by an order of magnitude. The graphene ARPES intensity has a strong photon energy dependence including resonances. The normal emission spectrum from the $π$-band shows a hitherto unreported, sharp resonance at a photon energy of 31 eV. The resonance is due to a 2$D$ interband transitions and highlights the importance of matrix element effects beyond the final state plane-wave approximation.
title A computational method for angle-resolved photoemission spectra from repeated-slab band structure calculations
topic Materials Science
url https://arxiv.org/abs/2402.17199