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arXiv · 2604.25598

Observation and Control of Moir\'e-Tailored Topological Dirac States

R. Ganser·M. P. T. Masilamani·B. Geldiyev·M. M. Hirschmann·A. Consiglio·J. Schusser·D. Di Sante·M. Ünzelmann·F. Reinert
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Abstract

Moir\'e heterostructures provide a powerful framework for tailoring electronic band structures via controlled long-range periodic superlattice potentials. Beyond widely studied moir\'e-tailored flat bands, folded band structures can host emergent Dirac states, which have recently attracted considerable interest. Direct momentum-resolved observation of gapless moir\'e-Dirac quasiparticles, however, is challenging and has so far remained elusive. By performing angle-resolved photoemission spectroscopy measurements on an epitaxial surface-moir\'e structure, we here provide direct spectroscopic evidence of moir\'e-dressed Dirac states with topological character. Driven by the one-dimensional superlattice potential, electrons propagate anisotropically with a weak but massless Dirac dispersion along the confinement direction. The observed band crossings belong to topological nodal lines pinned to the mini-Brillouin zone boundaries. As such, they are enforced and robustly protected by the non-symmorphic symmetry of the superlattice. Finally, we demonstrate that the topological excitations can be almost continuously controlled by tuning the moir\'e lattice periodicity, directly unveiling moir\'e heterostructures as a promising platform for creating and controlling topological moir\'e-Dirac states.

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R. Ganser, M. P. T. Masilamani, B. Geldiyev, M. M. Hirschmann, A. Consiglio, J. Schusser, D. Di Sante, M. Ünzelmann, F. Reinert. 2026-04-28. Observation and Control of Moir\'e-Tailored Topological Dirac States. https://arxiv.org/abs/2604.25598

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