Dresden 2026 – scientific programme
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MA: Fachverband Magnetismus
MA 7: Poster Magnetism I
MA 7.34: Poster
Monday, March 9, 2026, 09:30–12:30, P2
Exploring Quantum Geometry in the Dual Topological Insulator BiTe — •Maksim Povolotskiy1, Renjith Mathew Roy1, Ji Eun Lee1, Yanpeng Qi2, and Martin Dressel1 — 11. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany — 2School of Physical Science and Technology, Shanghai Tech University, Shanghai 201210, China
We present an optical spectroscopy study of the dual topological insulator bismuth telluride (BiTe) over a broad infrared range (from 5 meV to 2.5 eV), supported by transport measurements and ab initio calculations. BiTe, a member of the (Bi2)m(Bi2Te3)n homologous series, hosts both weak topological insulator (WTI) and topological crystalline insulator (TCI) surface states [1]. High pressure, low temperatures, and directional magnetic fields are applied to access and probe distinct electronic states located on different crystal facets. By systematically varying the measurement geometry and external conditions, the optical response aims to distinguish bulk contributions from surface states protected by different symmetries: time-reversal symmetry in the WTI and crystalline symmetry in the TCI [2]. Additionally, the analysis focuses on signatures of quantum geometric effects on electron-phonon coupling, which are expected to manifest as anomalies in the infrared-active phonon modes and reflect nontrivial Berry curvature in the electronic bands [3]. The results offer perspectives on the interplay between topology, lattice vibrations, and quantum geometry in BiTe. [1] Nat Commun 8, 14976 (2017) [2] Nat. Mater. 19, 610 (2020) [3] arXiv:2410.09677 (2024)
Keywords: Dual topological insulator; Infrared optical spectroscopy; Quantum geometry; Surface electron dynamics