2020/03/24 by Wenchao Jiang, Bowen Li, Xiaomeng Wang +10 · 19 citations
Materials Science · Mathematics · Physics and Astronomy · #Condensed matter physics #Doping #Electron #Geometry #Graphene research and applications #Materials science #Mathematics #Physics #Quantum many-body systems #Quantum mechanics #Singularity #Topological Materials and Phenomena #Topological insulator #Van Hove singularity #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.101.121115
published in Physical review. B./Physical review. B 101(12) (American Physical Society) · 6 pages, 4 figures
openalex publication_date 2020/03/24 · openalex created_date 2020/04/03 · arxiv created 2021/01/08 · arxiv updated 2021/01/11 · openalex updated_date 2026/08/05
The optical properties of Sn-doped Bi1.1Sb0.9Te2S, the most bulk-insulating topological insulator thus far, have been examined at different temperatures over a broad frequency range. No Drude response is detected in the low-frequency range down to 30\phantom\rule0.16em0excm^\ensuremath-1, corroborating the excellent bulk-insulating property of this material. Intriguingly, we observe a sharp peak at about 2200\phantom\rule0.16em0excm^\ensuremath-1 in the optical conductivity at 5 K. Further quantitative analyses of the line shape and temperature dependence of this sharp peak, in combination with first-principles calculations, suggest that it corresponds to a van Hove singularity arising from Mexican-hat-shaped inverted bands. Such a van Hove singularity is a pivotal ingredient of various strongly correlated phases.