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

Journal Article · Fri Aug 07 00:00:00 EDT 2015 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4928204· OSTI ID:22494701

Takagaki, Y. ^[1]

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1. Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin (Germany)

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.

• OSTI ID: 22494701
• Journal Information: Journal of Applied Physics, Vol. 118, Issue 5; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

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