Probing excitons with time-resolved momentum microscopy
2024-02-22 | preprint. A publication with affiliation to the University of Göttingen.
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- Authors
- Reutzel, Marcel; Jansen, G. S. Matthijs ; Mathias, Stefan
- Abstract
- Excitons -- two-particle correlated electron-hole pairs -- are the dominant low-energy optical excitation in the broad class of semiconductor materials, which range from classical silicon to perovskites, and from two-dimensional to organic materials. Recently, the study of excitons has been brought on a new level of detail by the application of photoemission momentum microscopy -- a technique that has dramatically extended the experimental capabilities of time- and angle-resolved photoemission spectroscopy (trARPES). Here, we review how the energy- and momentum-resolved photoelectron detection scheme enables direct access to the energy landscape of bright and dark excitons, and, more generally, to the momentum-coordinate of the exciton that is fundamental to its wavefunction. Focusing on two-dimensional materials and organic semiconductors as two tuneable platforms for exciton physics, we first discuss the typical photoemission fingerprint of excitons in momentum microscopy and highlight that is is possible to obtain information not only on the electron- but also hole-component of the former exciton. Second, we focus on the recent application of photoemission orbital tomography to such excitons, and discuss how this provides a unique access to the real-space properties of the exciton wavefunction. Throughout the review, we detail how studies performed on two-dimensional transition metal dichalcogenides and organic semiconductors lead to very similar conclusions, and, in this manner, highlight the strength of time-resolved momentum microscopy for the study of optical excitations in semiconductors.
- Issue Date
- 22-February-2024
- Project
- SFB 1073 | Topical Area B | B07 Elementare Schritte der Energiekonversion in stark angeregten korrelierten Materialien
SFB 1073 | Topical Area B | B10 Kontrolle der Energiekonversion von (opto-)elektronischen Eigenschaften in zweidimensionalen Materialien durch Manipulation von Drehwinkel und Stapelreihenfolge
SFB 1456 | Cluster B | B01: Mathematics of atomic orbital tomography - Organization
- I. Physikalisches Institut - Tieftemperaturphysik
- Working Group
- RG Mathias (Ultrafast Dynamics)