Freiburg 2019 – wissenschaftliches Programm
Sitzungen | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
FM: Fall Meeting
FM 81: Enabling Technologies: Quantum Materials
FM 81.2: Talk
Donnerstag, 26. September 2019, 14:30–14:45, 3042
Quantized conductance in topological insulators revealed by the Shockley-Ramo theorem — Paul Seifert1,2,3, Marinus Kundinger1,2, Gang Shi4, Xiaoyue He4, Kehui Wu4, Yongqing Li4, Alexander Holleitner1,2, and •Christoph Kastl1,2 — 1Walter Schottky Institut and Physics Department, Technical University of Munich, Am Coulombwall 4a, 85748 Garching, Germany — 2Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, 80799 Munich, Germany — 3ICFO-Institut de Ciencies Fotoniques, Castelldefels, Barcelona, 08860, Spain — 4Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
Materials with topological order promise coherent transport phenomena even in the presence of disorder and potentially at room temperature. Here, we image the local conductance of helical surface modes in the prototypical topological insulators Bi2Se3 and BiSbTe3. We apply the Shockley-Ramo theorem to design an optoelectronic probe circuit for the surface states, and find a conductance quantization at e2/h without any external magnetic field. The unprecedented response is a signature of local spin-polarized transport, and it can be switched on and off via an electrostatic field effect. The read-out does not require coherent transport between electrodes, in contrast to the Landauer-Büttiker description. It provides a generalizable platform for non-trivial gapless systems, such as Weyl-semimetals and quantum spin-Hall insulators. [1] P. Seifert et al. Quantized Conductance in Topological Insulators Revealed by the Shockley-Ramo Theorem. Phys. Rev. Lett. 122, 146804 (2019).