Spin relaxation and antiferromagnetic coupling in semiconductor quantum dots

A. Tackeuchi, T. Kuroda, K. Yamaguchi, Y. Nakata, N. Yokoyama, T. Takagahara

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

We report carrier spin dynamics in highly uniform self-assembled InAs quantum dots and the observation of antiferromagnetic coupling between semiconductor quantum dots. The spin relaxation times in the ground state and the first excited state were measured to be 1.0 and 0.6 ns, respectively, without the disturbance of inhomogeneous broadening. The measured spin relaxation time decreases rapidly from 1.1 ns at 10 K to 200 ps at 130 K. This large change in the spin relaxation time is well-explained in terms of the mechanism of acoustic phonon emission. In coupled quantum dots, the formation of antiferromagnetic coupling is directly observed. Electron spins are found to flip at 80 ps after photoexcitation via the interdot exchange interaction. The antiferromagnetic coupling exists at temperatures lower than 50-80 K. A model calculation based on the Heitler-London approximation supports the finding that the antiferromagnetic coupling is observable at low temperature. These carrier spin features in quantum dots are suitable for the future quantum computation.

Original languageEnglish
Pages (from-to)354-358
Number of pages5
JournalPhysica E: Low-Dimensional Systems and Nanostructures
Volume32
Issue number1-2 SPEC. ISS.
DOIs
Publication statusPublished - 2006 May 1

Keywords

  • Antiferromagnetism
  • D'yakonov-Perel'
  • Elliott-Yafet
  • InAs
  • Quantum dot
  • Semiconductor
  • Spin
  • Spin relaxation

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics

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