• DOI:10.1126/sciadv.aba4625
• Corpus ID: 214743375

Emergent quantum Hall effects below 50 mT in a two-dimensional topological insulator

@article{Shamim2020EmergentQH,
  title={Emergent quantum Hall effects below 50 mT in a two-dimensional topological insulator},
  author={Saquib Shamim and Wouter Beugeling and Jan B{\"o}ttcher and Pragya Shekhar and Andreas Budewitz and Philipp Leubner and Lukas Lunczer and Ewelina M. Hankiewicz and Hartmut Buhmann and Laurens W. Molenkamp},
  journal={Science Advances},
  year={2020},
  volume={6}
}

• S. Shamim, W. Beugeling, +7 authors L. Molenkamp
• Published 31 March 2020
• Physics
• Science Advances

Quantum Hall effects emerge at very low magnetic fields from helical edge channels in topological HgTe quantum wells. The realization of the quantum spin Hall effect in HgTe quantum wells has led to the development of topological materials, which, in combination with magnetism and superconductivity, are predicted to host chiral Majorana fermions. However, the large magnetization in conventional quantum anomalous Hall systems makes it challenging to induce superconductivity. Here, we report two different emergent quantum Hall effects in (Hg,Mn)Te quantum wells. First, a previously unidentified quantum Hall state emerges from the quantum spin Hall state at an exceptionally low magnetic field of ~50 mT. Second, tuning toward the bulk p-regime, we resolve quantum Hall plateaus at fields as low as 20 to 30 mT, where transport is dominated by a van Hove singularity in the valence band. These emergent quantum Hall phenomena rely critically on the topological band structure of HgTe, and their occurrence at very low fields makes them an ideal candidate for realizing chiral Majorana fermions.