Extraction of the self energy and Eliashberg function from angle resolved photoemission spectroscopy using the xARPES code

Fuente: arXiv
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Main Authors: van Waas, Thomas P., Berthod, Christophe, Berges, Jan, Marzari, Nicola, Dil, J. Hugo, Poncé, Samuel
Format: Preprint
Published: 2025
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_version_ 1866910178325037056
author van Waas, Thomas P.
Berthod, Christophe
Berges, Jan
Marzari, Nicola
Dil, J. Hugo
Poncé, Samuel
author_facet van Waas, Thomas P.
Berthod, Christophe
Berges, Jan
Marzari, Nicola
Dil, J. Hugo
Poncé, Samuel
contents Angle-resolved photoemission spectroscopy is a powerful experimental technique for studying anisotropic many-body interactions through the electron spectral function. Existing attempts to decompose the spectral function into non-interacting dispersions and electron-phonon, electron-electron, and electron-impurity self-energies rely on linearization of the bands and manual assignment of self-energy magnitudes. Here, we show how self-energies can be extracted consistently for curved dispersions. We extend the maximum-entropy method to Eliashberg-function extraction with Bayesian inference, optimizing the parameters describing the dispersions and the magnitudes of electron-electron and electron-impurity interactions. We compare these novel methodologies with state-of-the-art approaches on model data, then demonstrate their applicability with two high-quality experimental data sets. With the first set, we identify the phonon modes of a two-dimensional electron liquid on TiO$_2$-terminated SrTiO$_3$. With the second set, we obtain unprecedented agreement between two Eliashberg functions of Li-doped graphene extracted from separate dispersions. We release these functionalities in the novel Python code xARPES.
format Preprint
id arxiv_https___arxiv_org_abs_2508_13845
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Extraction of the self energy and Eliashberg function from angle resolved photoemission spectroscopy using the xARPES code
van Waas, Thomas P.
Berthod, Christophe
Berges, Jan
Marzari, Nicola
Dil, J. Hugo
Poncé, Samuel
Materials Science
Superconductivity
Computational Physics
Angle-resolved photoemission spectroscopy is a powerful experimental technique for studying anisotropic many-body interactions through the electron spectral function. Existing attempts to decompose the spectral function into non-interacting dispersions and electron-phonon, electron-electron, and electron-impurity self-energies rely on linearization of the bands and manual assignment of self-energy magnitudes. Here, we show how self-energies can be extracted consistently for curved dispersions. We extend the maximum-entropy method to Eliashberg-function extraction with Bayesian inference, optimizing the parameters describing the dispersions and the magnitudes of electron-electron and electron-impurity interactions. We compare these novel methodologies with state-of-the-art approaches on model data, then demonstrate their applicability with two high-quality experimental data sets. With the first set, we identify the phonon modes of a two-dimensional electron liquid on TiO$_2$-terminated SrTiO$_3$. With the second set, we obtain unprecedented agreement between two Eliashberg functions of Li-doped graphene extracted from separate dispersions. We release these functionalities in the novel Python code xARPES.
title Extraction of the self energy and Eliashberg function from angle resolved photoemission spectroscopy using the xARPES code
topic Materials Science
Superconductivity
Computational Physics
url https://arxiv.org/abs/2508.13845