Modal analysis applied to quantum waveguide structures and discontinuities

Andreas Weisshaar, Stephen M. Goodnick, Vijai K. Tripathi

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Modal expansions of the wave function together with a mode-matching method are utilized to analyze quantum waveguide structures and discontinuities. The modal expansion in the discontinuity region is simplified by employing a decomposition technique. The numerical behavior of the method is illustrated for a step discontinuity. It is shown that the computational cost is significantly reduced when the mode ratio is approximately 1.5 times the corresponding ratio in widths. Assuming an infinite lateral potential confinement, conductance calculations for a single and double bend configuration are compared to the idealized uniform quantum waveguide and display a reduction in the overall slope. The infinite lateral potential (hard wall) confinement is compared to a more realistic parabolic-like potential (soft wall) confinement for the case of a uniform narrow constriction. Utilizing the method of moments, the lateral eigensolutions for soft wall confinement are expanded in infinite square-well eigenfunctions. Conductance calculations for the uniform narrow constriction show a small increase in the resonant structure for soft wall confinement compared to hard wall confinement.

Original languageEnglish (US)
Pages (from-to)37-41
Number of pages5
JournalSuperlattices and Microstructures
Issue number1
StatePublished - 1992
Externally publishedYes

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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