@article{KrivenkovMarchenkoSanchezBarrigaetal.2021,
  author    = {Krivenkov, Maxim and Marchenko, Dimitry and S{\´a}nchez-Barriga, Jaime and Golias, Evangelos and Rader, Oliver and Varykhalov, Andrei},
  title     = {Origin of the band gap in Bi-intercalated graphene on Ir(111)},
  series = {2D Materials},
  volume    = {8},
  journal   = {2D Materials},
  number    = {3},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {2053-1583},
  doi       = {10.1088/2053-1583/abd1e4},
  pages     = {15},
  year      = {2021},
  abstract  = {Proximity to heavy sp-elements is considered promising for reaching a band gap in graphene that could host quantum spin Hall states. The recent report of an induced spin-orbit gap of 0.2 eV in Pb-intercalated graphene detectable by spin-resolved photoemission has spurred renewed interest in such systems (Klimovskikh et al 2017 ACS Nano 11, 368). In the case of Bi intercalation an even larger band gap of 0.4 eV has been observed but was assigned to the influence of a dislocation network (Warmuth et al 2016 Phys. Rev. B 93, 165 437). Here, we study Bi intercalation under graphene on Ir(111) and report a nearly ideal graphene dispersion without band replicas and no indication of hybridization with the substrate. The band gap is small (0.19 eV) and can be tuned by +/- 25 meV through the Bi coverage. The Bi atomic density is higher than in the recent report. By spin-resolved photoemission we exclude induced spin-orbit interaction as origin of the gap. Quantitative agreement of a photoemission intensity analysis with the measured band gap suggests sublattice symmetry breaking as one of the possible band gap opening mechanisms. We test several Bi structures by density functional theory. Our results indicate the possibility that Bi intercalates in the phase of bismuthene forming a graphene-bismuthene van der Waals heterostructure.},
  language  = {en}
}
@article{OvsyannikovKarlssonLundqvistetal.2013,
  author    = {Ovsyannikov, Ruslan and Karlsson, P. and Lundqvist, M. and Lupulescu, C. and Eberhardt, W. and F{\"o}hlisch, Alexander and Svensson, S. and Martensson, N.},
  title     = {Principles and operation of a new type of electron spectrometer - ArTOF},
  series = {Journal of electron spectroscopy and related phenomena : the international journal on theoretical and experimental aspects of electron spectroscopy},
  volume    = {191},
  journal   = {Journal of electron spectroscopy and related phenomena : the international journal on theoretical and experimental aspects of electron spectroscopy},
  number    = {12},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0368-2048},
  doi       = {10.1016/j.elspec.2013.08.005},
  pages     = {92 -- 103},
  year      = {2013},
  abstract  = {A new energy and angular electron analyzer ArTOF (Angular Resolved Time of Flight) is described. The analyzer is based on simultaneous measurement of flight times and angles in an advanced electron lens system. In angular modes the new analyzer combines an increase in transmission by almost three orders of magnitude with improved resolution, in comparison to standard state-of-the-art electron spectrometers. In this report we describe some design principles and we give a review of calibration and alignment procedures necessary for the use of the ArTOF on a synchrotron radiation facility. Our program scripts to handle the large datasets are also discussed. Furthermore we give a broad description of the new research fields that benefit from the use of the ArTOF and give a short summary of the first results of angle resolved photoemission measurement with ArTOF using the single-bunch X-ray pulses from the BESSY II storage ring facility. (C) 2013 Published by Elsevier B.V.},
  language  = {en}
}