@article{StuehlerKowalewskiReisetal.2022,
  author    = {St{\"u}hler, R. and Kowalewski, A. and Reis, F. and Jungblut, D. and Dominguez, F. and Scharf, B. and Li, G. and Sch{\"a}fer, J. and Hankiewicz, E. M. and Claessen, R.},
  title     = {Effective lifting of the topological protection of quantum spin Hall edge states by edge coupling},
  series = {Nature Communications},
  volume    = {13},
  journal   = {Nature Communications},
  doi       = {10.1038/s41467-022-30996-z},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-300886},
  year      = {2022},
  abstract  = {The scientific interest in two-dimensional topological insulators (2D TIs) is currently shifting from a more fundamental perspective to the exploration and design of novel functionalities. Key concepts for the use of 2D TIs in spintronics are based on the topological protection and spin-momentum locking of their helical edge states. In this study we present experimental evidence that topological protection can be (partially) lifted by pairwise coupling of 2D TI edges in close proximity. Using direct wave function mapping via scanning tunneling microscopy/spectroscopy (STM/STS) we compare isolated and coupled topological edges in the 2D TI bismuthene. The latter situation is realized by natural lattice line defects and reveals distinct quasi-particle interference (QPI) patterns, identified as electronic Fabry-P{\´e}rot resonator modes. In contrast, free edges show no sign of any single-particle backscattering. These results pave the way for novel device concepts based on active control of topological protection through inter-edge hybridization for, e.g., electronic Fabry-P{\´e}rot interferometry.},
  language  = {en}
}
@article{WagnerCrippaAmariccietal.2023,
  author    = {Wagner, N. and Crippa, L. and Amaricci, A. and Hansmann, P. and Klett, M. and K{\"o}nig, E. J. and Sch{\"a}fer, T. and Di Sante, D. and Cano, J. and Millis, A. J. and Georges, A. and Sangiovanni, G.},
  title     = {Mott insulators with boundary zeros},
  series = {Nature Communications},
  volume    = {14},
  journal   = {Nature Communications},
  doi       = {10.1038/s41467-023-42773-7},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-358150},
  year      = {2023},
  abstract  = {The topological classification of electronic band structures is based on symmetry properties of Bloch eigenstates of single-particle Hamiltonians. In parallel, topological field theory has opened the doors to the formulation and characterization of non-trivial phases of matter driven by strong electron-electron interaction. Even though important examples of topological Mott insulators have been constructed, the relevance of the underlying non-interacting band topology to the physics of the Mott phase has remained unexplored. Here, we show that the momentum structure of the Green's function zeros defining the "Luttinger surface" provides a topological characterization of the Mott phase related, in the simplest description, to the one of the single-particle electronic dispersion. Considerations on the zeros lead to the prediction of new phenomena: a topological Mott insulator with an inverted gap for the bulk zeros must possess gapless zeros at the boundary, which behave as a form of "topological antimatter" annihilating conventional edge states. Placing band and Mott topological insulators in contact produces distinctive observable signatures at the interface, revealing the otherwise spectroscopically elusive Green's function zeros.},
  language  = {en}
}