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arXiv · 2506.02137

Line shapes in time- and angle-resolved photoemission spectroscopy explored by machine learning

Tami C. Meyer·Gesa-R. Siemann·Paulina Majchrzak·Thomas Seyller·Jennifer Rigden·Yu Zhang·Emma Springate·Charlotte Sanders·Philip Hofmann
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Abstract

Time- and angle-resolved photoemission spectroscopy is a powerful technique for investigating the dynamics of excited carriers in quantum materials. Typically, data analysis proceeds via the inspection of time distribution curves (TDCs), which represent the time-dependent photoemission intensity in a region of interest -- often chosen somewhat arbitrarily -- in energy-momentum space. Here, we employ $k$-means, an unsupervised machine learning technique, to systematically investigate trends in TDC line shape for quasi-free-standing monolayer graphene and for a simple analytical model. Our analysis reveals how finite energy and time resolution can affect the TDC line shape. We discuss how this can be taken into account in a quantitative analysis, and under what conditions the time-dependent photoemission intensity after laser excitation can be approximated by a simple exponential decay.

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Tami C. Meyer, Gesa-R. Siemann, Paulina Majchrzak, Thomas Seyller, Jennifer Rigden, Yu Zhang, Emma Springate, Charlotte Sanders, Philip Hofmann. 2025-06-02. Line shapes in time- and angle-resolved photoemission spectroscopy explored by machine learning. https://arxiv.org/abs/2506.02137

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