Effect of an impurity in a quantum resonator

Y. Takagaki, D. K. Ferry

Research output: Contribution to journalArticlepeer-review

37 Scopus citations


We present a numerical study of the influence of disorder on quantum-mechanical transmission by considering the presence of an impurity in a T-shaped quantum-wire junction. The device is modeled as an electron waveguide of finite cross section. Transmission and reflection probabilities are computed by use of a waveguide-matching technique. The calculations show that the transmission of the two-dimensional electron gas through the narrow-wide-narrow geometry can be both enhanced and suppressed by the presence of a repulsive impurity potential. Although perfect transparency is not generally achieved with the presence of a single impurity, we find a 100% modulation of conductance as one device parameter is changed, which is robust against the scattering. If the impurity is located in the narrow-wire region, a periodic oscillation appears in transmission due to multiple reflections between the impurity and the stub region. We also examine an attractive scatterer.

Original languageEnglish (US)
Pages (from-to)6715-6720
Number of pages6
JournalPhysical Review B
Issue number12
StatePublished - 1992

ASJC Scopus subject areas

  • Condensed Matter Physics


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