@article{OkadaRotenbergKevanetal.2013,
  author    = {Okada, Michio and Rotenberg, Eli and Kevan, S. D. and Sch{\"a}fer, J. and Ujfalussy, Balazs and Stocks, G. Malcolm and Genatempo, B. and Bruno, E. and Plummer, E. W.},
  title     = {Evolution of the electronic structure in \(Mo_{1-x}Re_x\) alloys},
  series = {New Journal of Physics},
  volume    = {15},
  journal   = {New Journal of Physics},
  number    = {093010},
  issn      = {1367-2630},
  doi       = {10.1088/1367-2630/15/9/093010},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-122993},
  year      = {2013},
  abstract  = {We report a detailed experimental and theoretical study of the electronic structure of \(Mo_{1-x}Re_x\) random alloys. We have measured electronic band dispersions for clean and hydrogen-covered \(Mo_{1-x}Re_x\) ( 110) with x = 0-0.25 using angle-resolved photoemission spectroscopy. Our results suggest that the bulk and most surface electronic bands shift relative to the Fermi level systematically and approximately rigidly with Re concentration. We distinguish and quantify two contributions to these shifts: a raise of the Fermi energy and an increase of the overall bandwidth. Alloy bands calculated using the first-principles Korringa-Kohn-Rostoker coherent-potential-approximation method accurately predict both of these effects. As derived from the rigid band model, the Fermi energy shift is inversely related to the bulk density of states in this energy region. Using our results, we also characterize an electronic topological transition of the bulk Fermi surface and relate this to bulk transport properties. Finally, we distinguish effects beyond the rigid band approximation: a highly surface-localized state and a composition-dependent impact of the spin-orbit interaction.},
  language  = {en}
}
@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}
}