Exciton states in a two-dimensional systems of GaAs/AlAs multi-quantum wells under high magnetic fields

T. Yasui, Y. Segawa, Y. Aoyagi, Y. Iimura, G. E.W. Bauer, I. Mogi, G. Kido

Research output: Contribution to journalArticlepeer-review

Abstract

Magneto-optical spectra of a GaAs/AlAs multi-quantum-well sample have been measured in the Faraday configuration at high magnetic fields up to 25 T. These spectra reveal clear excitonic effects on top of the Landau-level structure. The excitonic states are well explained by effective mass calculations that take into account residual electric fields in the sample and the valence band mixing in magnetic fields. The results indicate that Coulomb interaction plays an important role even under very high magnetic fields, in contrast to the common belief that it should be only a weak perturbation to the Landau level. A crossing of the lowest heavy hole free exciton and the lowest light hole free exciton is observed at a magnetic field of about 15 T with σ+ polarization, thus achieving a symmetry change in the exciton ground state. The absence of an anticrossing between the light and heavy hole exciton ground state indicate the unimportance of exchange effects.

Original languageEnglish
Pages (from-to)275-282
Number of pages8
JournalScience Reports of the Rerearch Institutes Tohoku University Series A-Physics
Volume42
Issue number2
Publication statusPublished - 1996 May

Keywords

  • Coulomb interaction
  • Landau levels
  • Magnetoexciton
  • Quamtum well

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Metals and Alloys

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