Ultrafast signatures of Dirac / flat-band hybrid states from time-resolved ARPES
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arXiv
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| Auteurs principaux: | , , , , , , , , , , , , , , |
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| Format: | Preprint |
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2026
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| _version_ | 1866913164010979328 |
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| author | Federl, Maria-Elisabeth Gradl, Johannes Bergmeier, Franziska Weigl, Leonard Bruckmeier, Lukas Glaser, Theresa Mamiyev, Zamin Tegenkamp, Christoph Tilgner, Niclas Seyller, Thomas Tschirner, Teresa Convertino, Domenica Forti, Stiven Coletti, Camilla Gierz, Isabella |
| author_facet | Federl, Maria-Elisabeth Gradl, Johannes Bergmeier, Franziska Weigl, Leonard Bruckmeier, Lukas Glaser, Theresa Mamiyev, Zamin Tegenkamp, Christoph Tilgner, Niclas Seyller, Thomas Tschirner, Teresa Convertino, Domenica Forti, Stiven Coletti, Camilla Gierz, Isabella |
| contents | Hybridization of highly itinerant Dirac electrons with localized flat-band states is predicted to yield emergent phenomena such as exotic heavy-fermion behaviour. Epitaxial graphene on two-dimensional adsorbate structures on SiC(0001), which host flat bands, offers a promising platform to explore these effects. However, direct experimental evidence of interlayer hybridization in such systems has so far been lacking. Here, we address this gap using time- and angle-resolved photoemission spectroscopy (trARPES) where interlayer hybridization manifests in three key observations: (1) accelerated Dirac-carrier relaxation arising from additional electronic and phononic decay channels provided by the flat-band subsystem, (2) transient charging of the Dirac cone enabled by direct optical excitation from the flat bands, and (3) ultrafast back-transfer of charge into the flat bands on timescales governed by the interlayer coupling strength. We further demonstrate that the degree of hybridization can be tuned via the atomic number of the atoms intercalated at the graphene-SiC interface, establishing a controllable platform for investigating exotic correlated ground states. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2605_26873 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Ultrafast signatures of Dirac / flat-band hybrid states from time-resolved ARPES Federl, Maria-Elisabeth Gradl, Johannes Bergmeier, Franziska Weigl, Leonard Bruckmeier, Lukas Glaser, Theresa Mamiyev, Zamin Tegenkamp, Christoph Tilgner, Niclas Seyller, Thomas Tschirner, Teresa Convertino, Domenica Forti, Stiven Coletti, Camilla Gierz, Isabella Materials Science Hybridization of highly itinerant Dirac electrons with localized flat-band states is predicted to yield emergent phenomena such as exotic heavy-fermion behaviour. Epitaxial graphene on two-dimensional adsorbate structures on SiC(0001), which host flat bands, offers a promising platform to explore these effects. However, direct experimental evidence of interlayer hybridization in such systems has so far been lacking. Here, we address this gap using time- and angle-resolved photoemission spectroscopy (trARPES) where interlayer hybridization manifests in three key observations: (1) accelerated Dirac-carrier relaxation arising from additional electronic and phononic decay channels provided by the flat-band subsystem, (2) transient charging of the Dirac cone enabled by direct optical excitation from the flat bands, and (3) ultrafast back-transfer of charge into the flat bands on timescales governed by the interlayer coupling strength. We further demonstrate that the degree of hybridization can be tuned via the atomic number of the atoms intercalated at the graphene-SiC interface, establishing a controllable platform for investigating exotic correlated ground states. |
| title | Ultrafast signatures of Dirac / flat-band hybrid states from time-resolved ARPES |
| topic | Materials Science |
| url | https://arxiv.org/abs/2605.26873 |