Geometric blockade in a quantum dot coupled to two-dimensional and three-dimensional electron gases

K. Yamada, M. Stopa, T. Hatano, T. Yamaguchi, T. Ota, Y. Tokura, S. Tarucha

Research output: Contribution to journalArticle

Abstract

We fabricated a quantum dot coupled laterally to a two-dimensional electron gas and vertically to a three-dimensional electron gas in order to investigate the eigenstate dependence of tunneling rate to these gases. We observed a bias-dependent "geometric" current blockade. By tunneling via the asymmetric couplings, population inversion is induced and a dark metastable triplet state is revealed. The metastable state stops the current transport process, suppresses the current, and asymmetrically widens the Coulomb diamond. By analyzing the current as a function of source-drain and gate voltage and the magnetic field, we concluded that this effect is due to the geometric shape of the electronic states in the dot and the current is limited by the tunneling rate due to the eigenstates, that is, artificial σ coupling and π coupling.

Original languageEnglish
Article number201303
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume84
Issue number20
DOIs
Publication statusPublished - 2011 Nov 7

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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