Quantum interference in two independently tunable parallel quantum point contacts

J. A. Simmons, S. W. Hwang, D. C. Tsui, M. Shayegan

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

We have fabricated two independently tunable quantum point contacts in a parallel configuration, by wet etching a 2,000 Å diameter hole in the center of the constriction of a split-gate quantum point contact in an AlGaAs/GaAs heterojunction. The number of occupied subbands in each of the two channels on either side of the etched hole can be tuned independently by biasing the gates, with each channel exhibiting quantized conductance steps at integer multiples of 2e2/h, independent of the other. For B in the quantum Hall regime, periodic resistance oscillations are observed when both gate biases are fixed and B is swept. Further, periodic resistance oscillations are also observed when B and the bias on one gate is fixed, while the bias on the second gate is swept. In both cases the fluctuations are due to tunneling between opposite edge channels via magnetically bound 'edge' states encircling the etched hole, whose energies are quantized such that each encloses an integral number of flux quanta.

Original languageEnglish (US)
Pages (from-to)223-227
Number of pages5
JournalSuperlattices and Microstructures
Volume11
Issue number2
DOIs
StatePublished - 1992

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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