Thermopower evidence for Wigner crystallization in the insulating phase of two-dimensional GaAs bilayer hole systems

S. Faniel, E. Tutuc, E. P. De Poortere, C. Gustin, A. Vlad, L. Moldovan, S. Melinte, M. Shayegan, V. Bayot

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

We report on low-temperature thermopower measurements of interacting GaAs bilayer hole systems in the limit of no interlayer tunneling. These systems exhibit a reentrant insulating phase near the many-body quantum Hall state (QHS) at total filling factor ν = 1, when both layers have the same density. The diffusion thermopower is expected to diverge as T- 1 in the presence of an energy gap (Wigner crystal) or to vanish in the case of a disordered induced mobility gap. Our results show that, as the temperature is decreased, the diffusion thermopower exhibits a T- 1 dependence in the insulating phase around ν = 1. This behavior clearly indicates the opening of an energy gap at low temperature, in agreement with the formation of a pinned Wigner solid. Finally, we report on the T-dependence of the thermopower at ν = 1.

Original languageEnglish (US)
Pages (from-to)120-123
Number of pages4
JournalPhysica E: Low-Dimensional Systems and Nanostructures
Volume34
Issue number1-2
DOIs
StatePublished - Aug 1 2006

All Science Journal Classification (ASJC) codes

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

Keywords

  • Insulating phase
  • Quantum Hall effect
  • Thermopower
  • Wigner crystal

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