Microscopic Insights into Magnetic Warping and Time‐Reversal Symmetry Breaking in Topological Surface States of Rare‐Earth‐Doped Bi <sub>2</sub> Te <sub>3</sub>
Magnetic interactions at the surface of topological insulators provide a versatile route to engineer exotic quantum states. Breaking time-reversal symmetry (TRS) at the topological surface state (TSS) enables the opening of a Dirac gap, which is essential for realizing quantum anomalous Hall physics. This work investigates the impact of submonolayer deposition of magnetic rare-earth adatoms on the prototypical topological insulator Bi<sub>2</sub>Te<sub>3</sub>. Scanning tunneling microscopy (STM) supported by first-principle calculations, core-level photoemission spectroscopy (XPS), angle-resolved photoemission spectroscopy (ARPES), X-ray magnetic circular dichroism (XMCD) and quasiparticle interference (QPI) mapping are combined to reveal direct evidence of local interactions between erbium (Er) atoms and the substrate, leading to significant modifications of the TSS. XMCD measurements confirm the out-of-plane magnetic anisotropy for Er adatoms on Bi<sub>2</sub>Te<sub>3</sub> , which induces a warping transition of the Fermi surface from a snowflake to a star-of-David-like geometry, along with a Dirac point gap opening and spectral splitting near the Γ point. QPI maps confirm the reconstructed surface band topology through modified scattering patterns consistent with TRS breaking. Our results identify a microscopic mechanism for magnetic interaction at the surface of a topological insulator and establish magnetic rare-earth doping as an effective strategy to tailor topological electronic states with atomic-scale control.
Authors
- A. Barla (ORCID: https://orcid.org/0000-0002-5632-4915)
- Massimo Tallarida (ORCID: https://orcid.org/0000-0002-1438-3466)
- Marc G. Cuxart (ORCID: https://orcid.org/0000-0002-9085-1225)
- Rodolfo Miranda (ORCID: https://orcid.org/0000-0002-1064-6724)
- Sergio O. Valenzuela (ORCID: https://orcid.org/0000-0002-4632-8891)
- Pierluigi Gargiani (ORCID: https://orcid.org/0000-0002-6649-0538)
- Miguel A. Valbuena (ORCID: https://orcid.org/0000-0002-0585-5636)
- A. I. Figueroa (ORCID: https://orcid.org/0000-0002-8498-9383)
- Amadeo L. Vázquez de Parga (ORCID: https://orcid.org/0000-0003-0551-1603)
- J. Dai (ORCID: https://orcid.org/0000-0003-1388-6843)
- Manuela Garnica (ORCID: https://orcid.org/0000-0002-7861-9490)
- Aitor Mugarza (ORCID: https://orcid.org/0000-0002-2698-885X)
- F. Calleja (ORCID: https://orcid.org/0000-0001-6007-8641)
- Beatriz Muñiz Cano (ORCID: https://orcid.org/0000-0002-9338-7077)
- F. Guinea (ORCID: https://orcid.org/0000-0001-5915-5427)
- Jose Ángel Silva-Guillén (ORCID: https://orcid.org/0000-0002-0483-5334)
- Vera Marinova (ORCID: https://orcid.org/0000-0002-3499-0212)
- Kevin García Díez (ORCID: https://orcid.org/0000-0001-8093-904X)
- Gustavo Molina (ORCID: https://orcid.org/0000-0002-1409-6846)
Institutions
- Madrid Institute for Advanced Studies (ES)
- Ikerbasque (ES)
- Institució Catalana de Recerca i Estudis Avançats (ES)
- Bulgarian Academy of Sciences (BG)
- ALBA Synchrotron (Spain) (ES)
- Institut Català de Nanociència i Nanotecnologia (ES)
- Institute of Structure of Matter (IT)
- Instituto de Ciencia de Materiales de Madrid (ES)
- Institute of Information and Communication Technologies (BG)
- Institut de Nanociència i Nanotecnologia de la Universitat de Barcelona
- Donostia International Physics Center (ES)
- Universidad Autónoma de Madrid (ES)
- Universitat de Barcelona (ES)
Publication Details
- Journal
- Advanced Materials
- Published
- 2025-11-04
- DOI
- https://doi.org/10.1002/adma.202510877
- Primary Topic
- Topological Materials and Phenomena
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Comunidad de Madrid
- European Commission
- Ministerio de Ciencia e Innovación
- Horizon 2020 Framework Programme
- European Regional Development Fund
- Agencia Estatal de Investigación