@article{ScharfBraggioStambinietal.2020,
  author    = {Scharf, Benedikt and Braggio, Alessandro and Stambini, Elia and Giazotto, Francesco and Hankiewicz, Ewelina M.},
  title     = {Topological Josephson heat engine},
  series = {Communications Physics},
  volume    = {3},
  journal   = {Communications Physics},
  doi       = {10.1038/s42005-020-00463-6},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-230603},
  year      = {2020},
  abstract  = {Topological superconductors represent a fruitful playing ground for fundamental research as well as for potential applications in fault-tolerant quantum computing. Especially Josephson junctions based on topological superconductors remain intensely studied, both theoretically and experimentally. The characteristic property of these junctions is their 4-periodic ground-state fermion parity in the superconducting phase difference. Using such topological Josephson junctions, we introduce the concept of a topological Josephson heat engine. We discuss how this engine can be implemented as a Josephson-Stirling cycle in topological superconductors, thereby illustrating the potential of the intriguing and fruitful marriage between topology and coherent thermodynamics. It is shown that the Josephson-Stirling cycle constitutes a highly versatile thermodynamic machine with different modes of operation controlled by the cycle temperatures. Finally, the thermodynamic cycle reflects the hallmark 4 pi -periodicity of topological Josephson junctions and could therefore be envisioned as a complementary approach to test topological superconductivity. Topological superconductors are expected to be a key component of quantum computing systems but reliably detecting their exotic properties is a challenge. Here, the authors propose a topological Josephson heat engine which uses thermodynamic effects to probe the 4 pi -periodic ground state of a topological superconductor.},
  language  = {en}
}
@article{ElsterPlattThomaleetal.2015,
  author    = {Elster, Lars and Platt, Christian and Thomale, Ronny and Hanke, Werner and Hankiewicz, Ewelina M.},
  title     = {Accessing topological superconductivity via a combined STM and renormalization group analysis},
  series = {Nature Communications},
  volume    = {6},
  journal   = {Nature Communications},
  number    = {8232},
  doi       = {10.1038/ncomms9232},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-148181},
  year      = {2015},
  abstract  = {The search for topological superconductors has recently become a key issue in condensed matter physics, because of their possible relevance to provide a platform for Majorana bound states, non-Abelian statistics, and quantum computing. Here we propose a new scheme which links as directly as possible the experimental search to a material-based microscopic theory for topological superconductivity. For this, the analysis of scanning tunnelling microscopy, which typically uses a phenomenological ansatz for the superconductor gap functions, is elevated to a theory, where a multi-orbital functional renormalization group analysis allows for an unbiased microscopic determination of the material-dependent pairing potentials. The combined approach is highlighted for paradigmatic hexagonal systems, such as doped graphene and water-intercalated sodium cobaltates, where lattice symmetry and electronic correlations yield a propensity for a chiral singlet topological superconductor. We demonstrate that our microscopic material-oriented procedure is necessary to uniquely resolve a topological superconductor state.},
  language  = {en}
}
@article{BrueneThienelStuiberetal.2014,
  author    = {Br{\"u}ne, Christoph and Thienel, Cornelius and Stuiber, Michael and B{\"o}ttcher, Jan and Buhmann, Hartmut and Novik, Elena G. and Liu, Chao-Xing and Hankiewicz, Ewelina M. and Molenkamp, Laurens W.},
  title     = {Dirac-Screening Stabilized Surface-State Transport in a Topological Insulator},
  series = {Physical Review X},
  volume    = {4},
  journal   = {Physical Review X},
  number    = {4},
  issn      = {2160-3308},
  doi       = {10.1103/PhysRevX.4.041045},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-118091},
  pages     = {041045},
  year      = {2014},
  abstract  = {We report magnetotransport studies on a gated strained HgTe device. This material is a three-dimensional topological insulator and exclusively shows surface-state transport. Remarkably, the Landau-level dispersion and the accuracy of the Hall quantization remain unchanged over a wide density range (3×1011  cm-2<n<2×1012  cm-2). These observations imply that even at large carrier densities, the transport is surface-state dominated, where bulk transport would have been expected to coexist already. Moreover, the density dependence of the Dirac-type quantum Hall effect allows us to identify the contributions from the individual surfaces. A k⋅p model can describe the experiments but only when assuming a steep band bending across the regions where the topological surface states are contained. This steep potential originates from the specific screening properties of Dirac systems and causes the gate voltage to influence the position of the Dirac points rather than that of the Fermi level.},
  language  = {en}
}