Emergence of Moiré Dirac Fermions at the Interface of Topological and 2D Magnetic Insulators
Year: 2025
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide Dirac Fermions on the surface of the topological insulator are spin-momentum locked and topologically protected, making them interesting for spintronics and quantum computing applications. When in proximity to magnetism and superconductivity, these electronic states could result in quantum anomalous Hall effect and Majorana Fermions, respectively. An even more dramatic enrichment of the topological insulators’ physics is expected for moiré superlattices, where, analogously to the twisted graphene layers, electronic correlations could be strongly enhanced, a task previously notoriously difficult to achieve in topological matter. Until now, the experimental confirmation of such moiré properties has remained elusive. Here, we grow the two-dimensional van der Waals magnetic insulators FeX 2 (where X = Cl or Br) on top of the topological insulator Bi 2 Se 3 and establish a moiré superlattice formation at the interface. By means of scanning tunneling microscopy and angle-resolved photoemission spectroscopy, we investigate the electronic properties of the formed moiré superlattice and demonstrate its tunability via the film choice. We reveal replicated Dirac cones and focus on their intersections, which, in the case of FeBr 2 /Bi 2 Se 3, occur below the Fermi level. We identify the signatures of small gaps at the intersections around the M̅ i points that we attribute to the moiré interaction. These findings point to the specific type of magnetic moiré potential that breaks the time-reversal symmetry at these points but not at the Γ̅ point. Our observations provide an intriguing scenario of correlated topological phases induced by moiré superlattice that may result in topological superconductivity, high Chern number phases, and exotic noncollinear magnetic textures.
Source: ACS Nano
Institutions: Donostia International Physics Center, Consejo Superior de Investigaciones Científicas, University of the Basque Country, Material Physics Center, Centre National de la Recherche Scientifique, Université Paris-Saclay, Institut des Sciences Moléculaires d'Orsay, ALBA Synchrotron (Spain), Institute of Physics, Institute of Photonic Sciences, Barcelona Institute of Science and Technology, Brookhaven National Laboratory, Universidad de Zaragoza, Instituto de Nanociencia y Materiales de Aragón
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
Funders: U.S. Department of Energy, “la Caixa” Foundation, Ministerio de Ciencia, Innovación y Universidades, European Commission, Eusko Jaurlaritza, Universidad de Zaragoza, Diputación Foral de Gipuzkoa, Fundación Bancaria Caixa d'Estalvis i Pensions de Barcelona, European Regional Development Fund, Agencia Estatal de Investigación, Basic Energy Sciences, European Social Fund, NextGenerationEU
Awards: G1204740081, G120905174, G1255325603, G1282293533, G154073810, G1847291448, G21330127, G2171898597, G2262748287, G2383463909, G241279073, G2542020899, G2927035355, G3480869486, G3681454997, G4033406476, G4042783231, G4098043432, G425668148, G451917667, G4993383890, G5132640529, G5178665745, G529962013, G5338730000, G5765906131, G5943232429, G5955501538, G5967599077, G6096076439, G6218905885, G6802180733, G6965541988, G7685134749, G7731791180, G8072286528, G8399864673
OpenAlex ID: W4415024844