Tunneling-induced fractal transmission in valley Hall waveguides
Shah T, Marquardt F, Peano V (2023)
Publication Type: Journal article
Publication year: 2023
Journal
Book Volume: 107
Article Number: 054304
Journal Issue: 5
DOI: 10.1103/PhysRevB.107.054304
Abstract
The valley Hall effect provides a popular route to engineer robust waveguides for bosonic excitations such as photons and phonons. The almost complete absence of backscattering in many experiments has its theoretical underpinning in a smooth-envelope approximation that neglects large momentum transfer and is accurate only for small bulk band gaps and/or smooth domain walls. For larger bulk band gaps and hard domain walls, backscattering is expected to become significant. Here, we show that in this experimentally relevant regime, the reflection of a wave at a sharp corner becomes highly sensitive to the orientation of the outgoing waveguide relative to the underlying lattice. Enhanced backscattering can be understood as being triggered by resonant tunneling transitions in quasimomentum space. Tracking the resonant tunneling energies as a function of the waveguide orientation reveals a self-repeating fractal pattern that is also imprinted in the density of states and the backscattering rate at a sharp corner.
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Germany (DE)How to cite
APA:
Shah, T., Marquardt, F., & Peano, V. (2023). Tunneling-induced fractal transmission in valley Hall waveguides. Physical Review B, 107(5). https://doi.org/10.1103/PhysRevB.107.054304
MLA:
Shah, Tirth, Florian Marquardt, and Vittorio Peano. "Tunneling-induced fractal transmission in valley Hall waveguides." Physical Review B 107.5 (2023).
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