Ultrafast Formation and Annihilation of Strongly Bound, Anisotropic Excitons

Fuente: arXiv
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Main Authors: Lloyd, Lawson T., Pincelli, Tommaso, Wahada, Mohamed Amine, De Vita, Alessandro, Menzel, Ferdinand, Mosina, Kseniia, Castro, Túlio H. L. G., Neef, Alexander, Stier, Andreas V., Wilson, Nathan P., Sofer, Zdeněk, Finley, Jonathan J., Wolf, Martin, Rettig, Laurenz, Ernstorfer, Ralph
Format: Preprint
Published: 2026
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author Lloyd, Lawson T.
Pincelli, Tommaso
Wahada, Mohamed Amine
De Vita, Alessandro
Menzel, Ferdinand
Mosina, Kseniia
Castro, Túlio H. L. G.
Neef, Alexander
Stier, Andreas V.
Wilson, Nathan P.
Sofer, Zdeněk
Finley, Jonathan J.
Wolf, Martin
Rettig, Laurenz
Ernstorfer, Ralph
author_facet Lloyd, Lawson T.
Pincelli, Tommaso
Wahada, Mohamed Amine
De Vita, Alessandro
Menzel, Ferdinand
Mosina, Kseniia
Castro, Túlio H. L. G.
Neef, Alexander
Stier, Andreas V.
Wilson, Nathan P.
Sofer, Zdeněk
Finley, Jonathan J.
Wolf, Martin
Rettig, Laurenz
Ernstorfer, Ralph
contents Van der Waals (vdW) layered materials with long-range magnetic order have the potential to enable novel optoelectronic and spintronic applications. Among these, CrSBr is an air-stable, direct band gap semiconductor that hosts interlayer antiferromagnetic order, a highly anisotropic electronic structure, and strongly bound excitons. In particular, excitons in CrSBr have been shown to inherit the quasi-one-dimensional nature of the material and also couple to the underlying spinorder. However, mechanisms of exciton formation, dissociation, and interaction with free carriers remain largely unexplored, despite being crucial for spintronic and optoelectronic applications. Here, we employ time- and angle-resolved photoemission spectroscopy to map the electronic structure and excited state dynamics in CrSBr. We directly resolve an exceptionally large exciton binding energy (~800 meV) and a highly anisotropic momentum space distribution of the exciton, revealing its quasi-1D real-space character. We observe an excitation-density-dependent interconversion between bound excitons and quasi-free carriers on sub- to few-picosecond timescales, indicating that many-body effects govern the excited-state dynamics and optical properties during the initial stages of relaxation. Our work highlights the strongly bound, anisotropic character of excitons in CrSBr, as well as the microscopic interactions steering relaxation pathways after photoexcitation in elevated density regimes relevant for future device applications.
format Preprint
id arxiv_https___arxiv_org_abs_2603_26294
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Ultrafast Formation and Annihilation of Strongly Bound, Anisotropic Excitons
Lloyd, Lawson T.
Pincelli, Tommaso
Wahada, Mohamed Amine
De Vita, Alessandro
Menzel, Ferdinand
Mosina, Kseniia
Castro, Túlio H. L. G.
Neef, Alexander
Stier, Andreas V.
Wilson, Nathan P.
Sofer, Zdeněk
Finley, Jonathan J.
Wolf, Martin
Rettig, Laurenz
Ernstorfer, Ralph
Materials Science
Van der Waals (vdW) layered materials with long-range magnetic order have the potential to enable novel optoelectronic and spintronic applications. Among these, CrSBr is an air-stable, direct band gap semiconductor that hosts interlayer antiferromagnetic order, a highly anisotropic electronic structure, and strongly bound excitons. In particular, excitons in CrSBr have been shown to inherit the quasi-one-dimensional nature of the material and also couple to the underlying spinorder. However, mechanisms of exciton formation, dissociation, and interaction with free carriers remain largely unexplored, despite being crucial for spintronic and optoelectronic applications. Here, we employ time- and angle-resolved photoemission spectroscopy to map the electronic structure and excited state dynamics in CrSBr. We directly resolve an exceptionally large exciton binding energy (~800 meV) and a highly anisotropic momentum space distribution of the exciton, revealing its quasi-1D real-space character. We observe an excitation-density-dependent interconversion between bound excitons and quasi-free carriers on sub- to few-picosecond timescales, indicating that many-body effects govern the excited-state dynamics and optical properties during the initial stages of relaxation. Our work highlights the strongly bound, anisotropic character of excitons in CrSBr, as well as the microscopic interactions steering relaxation pathways after photoexcitation in elevated density regimes relevant for future device applications.
title Ultrafast Formation and Annihilation of Strongly Bound, Anisotropic Excitons
topic Materials Science
url https://arxiv.org/abs/2603.26294