@article{WiedenmannBocquillonDeaconetal.2016,
  author    = {Wiedenmann, J. and Bocquillon, E. and Deacon, R.S. and Hartinger, S. and Herrmann, O. and Klapwijk, T.M. and Maier, L. and Ames, C. and Br{\"u}ne, C. and Gould, C. and Oiwa, A. and Ishibashi, K. and Tarucha, S. and Buhmann, H. and Molenkamp, L.W.},
  title     = {4π-periodic Josephson supercurrent in HgTe-based topological Josephson junctions},
  series = {Nature Communications},
  volume    = {7},
  journal   = {Nature Communications},
  doi       = {10.1038/ncomms10303},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-175353},
  year      = {2016},
  abstract  = {The Josephson effect describes the generic appearance of a supercurrent in a weak link between two superconductors. Its exact physical nature deeply influences the properties of the supercurrent. In recent years, considerable efforts have focused on the coupling of superconductors to the surface states of a three-dimensional topological insulator. In such a material, an unconventional induced p-wave superconductivity should occur, with a doublet of topologically protected gapless Andreev bound states, whose energies vary 4π-periodically with the superconducting phase difference across the junction. In this article, we report the observation of an anomalous response to rf irradiation in a Josephson junction made of a HgTe weak link. The response is understood as due to a 4π-periodic contribution to the supercurrent, and its amplitude is compatible with the expected contribution of a gapless Andreev doublet. Our work opens the way to more elaborate experiments to investigate the induced superconductivity in a three-dimensional insulator.},
  language  = {en}
}
@article{TanEloPuskaetal.2018,
  author    = {Tan, Z. B. and Elo, T. and Puska, A. and Sarkar, J. and L{\"a}hteenm{\"a}ki, P. and Duerr, F. and Gould, C. and Molenkamp, L. W. and Nagaev, K. E. and Hakonen, P. J.},
  title     = {Hanbury-Brown and Twiss exchange and non-equilibrium-induced correlations in disordered, four-terminal graphene-ribbon conductor},
  series = {Scientific Reports},
  volume    = {8},
  journal   = {Scientific Reports},
  doi       = {10.1038/s41598-018-32777-5},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-240348},
  year      = {2018},
  abstract  = {We have investigated current-current correlations in a cross-shaped conductor made of graphene. The mean free path of charge carriers is on the order of the ribbon width which leads to a hybrid conductor where there is diffusive transport in the device arms while the central connection region displays near ballistic transport. Our data on auto and cross correlations deviate from the predictions of Landauer-B{\"u}ttiker theory, and agreement can be obtained only by taking into account contributions from non-thermal electron distributions at the inlets to the semiballistic center, in which the partition noise becomes strongly modified. The experimental results display distinct Hanbury - Brown and Twiss (HBT) exchange correlations, the strength of which is boosted by the non-equilibrium occupation-number fluctuations internal to this hybrid conductor. Our work demonstrates that variation in electron coherence along atomically-thin, two-dimensional conductors has significant implications on their noise and cross correlation properties.},
  language  = {en}
}