• Corpus ID: 219177269

Higher-Order Topological Instanton Tunneling Oscillation

@article{Park2020HigherOrderTI,
  title={Higher-Order Topological Instanton Tunneling Oscillation},
  author={Moon Jip Park and Sunam Jeon and SungBin Lee and Hee Chul Park and Youngkuk Kim},
  journal={arXiv: Mesoscale and Nanoscale Physics},
  year={2020}
}

• Moon Jip Park, Sunam Jeon, +2 authors Youngkuk Kim
• Published 1 June 2020
• Physics
• arXiv: Mesoscale and Nanoscale Physics

We propose a new type of instanton interference effect in two-dimensional higher-order topological insulators. The intercorner tunneling consists of the instanton and the anti-instanton pairs that travel through the boundary of the higher-order topological insulator. The Berry phase difference between the instanton pairs causes the interference of the tunneling. This topological effect leads to the gate-tunable oscillation of the energy splitting between the corner states, where the oscillatory nodes signal the perfect suppression of the tunneling. We suggest this phenomenon as a unique feature of the topological corner states that differentiate from trivial bound states. In the view of experimental realization, we exemplify twisted bilayer graphene, as a promising candidate of a two-dimensional higher-order topological insulator. The oscillation can be readily observed through the transport experiment that we propose. Thus, our work provides a feasible route to identify higher-order topological materials.