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>
Abstract
Abstract 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 2 Te 3 . 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 2 Te 3 , 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.
Article Details
Authors (19)
Beatriz Muñiz Cano
Instituto Madrileño de Estudios Avanzados IMDEA Nanociencia Calle Faraday 9 Madrid 28049 Spain
Fabián Calleja
Instituto Madrileño de Estudios Avanzados IMDEA Nanociencia Calle Faraday 9 Madrid 28049 Spain
Ji Dai
ALBA Synchrotron Light Source Cerdanyola del Vallès Barcelona Spain 08290
Massimo Tallarida
ALBA Synchrotron Light Source Cerdanyola del Vallès Barcelona Spain 08290
Vera Marinova
Institute of Optical Materials and Technologies Bulgarian Academy of Sciences Sofia 1113 Bulgaria
Alessandro Barla
Istituto di Struttura della Materia (ISM) Consiglio Nazionale delle Ricerche (CNR) Trieste I‐34149 Italy
Marc G. Cuxart
Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST Campus UAB Barcelona 08193 Spain
Pierluigi Gargiani
Department of Materials ETH Zürich Zürich CH‐8093 Switzerland
Gonzalo N. Molina
Instituto Madrileño de Estudios Avanzados IMDEA Nanociencia Calle Faraday 9 Madrid 28049 Spain
Jose Angel Silva‐Guillén
Fundación IMDEA Nanociencia C/ Faraday 9, Campus Cantoblanco Madrid 28409 Spain
Adriana I. Figueroa
Departament de Física de la Matèria Condensada and IN2UB Universitat de Barcelona Barcelona 08028 Spain
Kevin García‐Díez
ALBA Synchrotron Light Source Cerdanyola del Vallès Barcelona Spain 08290
Sergio O. Valenzuela
Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST Campus UAB Barcelona 08193 Spain
Aitor Mugarza
Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Bellaterra Barcelona Spain
Amadeo L. Vázquez de Parga
Instituto Madrileño de Estudios Avanzados IMDEA Nanociencia Calle Faraday 9 Madrid 28049 Spain
Rodolfo Miranda
IMDEA Nanoscience, C/ Faraday 9 Campus De Cantoblanco Madrid Spain
Francisco Guinea
Instituto Madrileño de Estudios Avanzados Nanoscience
Manuela Garnica
Instituto Madrileño de Estudios Avanzados IMDEA Nanociencia Calle Faraday 9 Madrid 28049 Spain
Miguel A. Valbuena
Institution Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanoscience) Madrid 28049 Spain