Ultrafast electron dynamics upon above band-gap excitation in epitaxial LaFeO$_3$(001) thin films
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| Main Authors: | , , , , |
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| Format: | Preprint |
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2025
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| _version_ | 1866918040265818112 |
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| author | Wührl, Friederike Elisa Rieche, Antonia Oelschläger, Anne Dörr, Kathrin Widdra, Wolf |
| author_facet | Wührl, Friederike Elisa Rieche, Antonia Oelschläger, Anne Dörr, Kathrin Widdra, Wolf |
| contents | Strong electron correlations in perovskite oxides give rise to rich and often unexpected electronic phenomena. In this study, we present a comprehensive surface-science investigation of epitaxial thin films of the charge-transfer insulator LaFeO$_3$(001). The characterization includes low-energy electron diffraction (LEED), high-resolution electron energy loss spectroscopy (HREELS), and photoemission spectroscopy. We map both the occupied and unoccupied electronic states using two-photon photoemission (2PPE) spectroscopy. Furthermore, we probe electron dynamics through an ultraviolet-ultraviolet (UV-UV) pump-probe experiment, exciting electrons from hybridized O~$2p$/Fe $3d$ states to Fe minority-spin states above the band gap. Our results reveal three distinct unoccupied states, which we assign to Fe $t_{2g\downarrow}$, Fe $e_{g\downarrow}$, and La $5d$ orbitals. Notably, the conduction band minimum exhibits a biexponential decay with time constants of 39\,fs and 1100\,fs, suggesting the presence of two independent decay pathways. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2505_24809 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Ultrafast electron dynamics upon above band-gap excitation in epitaxial LaFeO$_3$(001) thin films Wührl, Friederike Elisa Rieche, Antonia Oelschläger, Anne Dörr, Kathrin Widdra, Wolf Materials Science Strong electron correlations in perovskite oxides give rise to rich and often unexpected electronic phenomena. In this study, we present a comprehensive surface-science investigation of epitaxial thin films of the charge-transfer insulator LaFeO$_3$(001). The characterization includes low-energy electron diffraction (LEED), high-resolution electron energy loss spectroscopy (HREELS), and photoemission spectroscopy. We map both the occupied and unoccupied electronic states using two-photon photoemission (2PPE) spectroscopy. Furthermore, we probe electron dynamics through an ultraviolet-ultraviolet (UV-UV) pump-probe experiment, exciting electrons from hybridized O~$2p$/Fe $3d$ states to Fe minority-spin states above the band gap. Our results reveal three distinct unoccupied states, which we assign to Fe $t_{2g\downarrow}$, Fe $e_{g\downarrow}$, and La $5d$ orbitals. Notably, the conduction band minimum exhibits a biexponential decay with time constants of 39\,fs and 1100\,fs, suggesting the presence of two independent decay pathways. |
| title | Ultrafast electron dynamics upon above band-gap excitation in epitaxial LaFeO$_3$(001) thin films |
| topic | Materials Science |
| url | https://arxiv.org/abs/2505.24809 |