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Title: Strong reflection and periodic resonant transmission of helical edge states in topological-insulator stub-like resonators

The helical edge states of two-dimensional topological insulators (TIs) experience appreciable quantum mechanical scattering in narrow channels when the width changes abruptly. The interference of the geometry scattering in narrow-wide-narrow waveguide structures is shown to give rise to the strong suppression of transmission when the incident energy is barely above the propagation threshold. Periodic resonant transmission takes place in this high reflection regime while the length of the wide section is varied. The resonance condition is governed by the transverse confinement in the wide section, where the form of quantization is manifested to differ for the two orthogonal directions. The confined energy levels in TI quantum dots are derived based on this observation. In addition, the off-diagonal spin-orbit term is found to produce an anomalous resonance state, which merges with the bottom ordinary resonance state to annihilate.
Authors:
 [1]
  1. Paul-Drude-Institut f√ľr Festk√∂rperelektronik, Hausvogteiplatz 5-7, 10117 Berlin (Germany)
Publication Date:
OSTI Identifier:
22494701
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 5; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CONFINEMENT; ELECTRICAL INSULATORS; ENERGY LEVELS; INTERFERENCE; L-S COUPLING; PERIODICITY; QUANTIZATION; QUANTUM DOTS; QUANTUM MECHANICS; REFLECTION; RESONANCE; RESONATORS; SCATTERING; TRANSMISSION; TWO-DIMENSIONAL SYSTEMS; WAVEGUIDES