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Ultrafast electron dynamics in a topological surface state observed in two-dimensional momentum space
We study ultrafast population dynamics in the topological surface state of Sb2Te3 in two-dimensional momentum space with time- and angle-resolved two-photon photoemission spectroscopy. Linearly polarized mid-infrared pump pulses are used to permit a direct optical excitation across the Dirac poin...
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| Auteurs principaux: | , , , , , , , |
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| Format: | Article |
| Langue: | anglais |
| Publié: |
Philipps-Universität Marburg
2023
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| Sujets: | |
| Accès en ligne: | Texte intégral en PDF |
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| Résumé: | We study ultrafast population dynamics in the topological surface state of Sb2Te3 in two-dimensional
momentum space with time- and angle-resolved two-photon photoemission spectroscopy. Linearly
polarized mid-infrared pump pulses are used to permit a direct optical excitation across the Dirac
point. We show that this resonant excitation is strongly enhanced within the Dirac cone along three
of the six ¯ Ŵ– ¯
M directions and results in a macroscopic photocurrent when the plane of incidence is
aligned along a ¯ Ŵ–¯
K direction. Our experimental approach makes it possible to disentangle the decay
of transiently excited population and photocurent by elastic and inelastic electron scattering within
the full Dirac cone in unprecedented detail. This is utilized to show that doping of Sb2Te3 by vanadium
atoms strongly enhances inelastic electron scattering to lower energies, but only scarcely affects
elastic scattering around the Dirac cone. |
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| Description: | Gefördert durch den Open-Access-Publikationsfonds der UB Marburg. |
| DOI: | 10.1038/s41598-023-32811-1 |