Optically pumped NMR in the quantum Hall regimes

P. Khandelwal, N. N. Kuzma, S. E. Barrett, L. N. Pfeiffer, K. W. West

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


We review our recent measurements of the 71Ga Knight shift and linewidth in two different electron-doped multiple quantum well samples using optically pumped NMR. These data are the first direct measurements of the electron spin polarization, ℘(v, T) ≡ 〈Sz(v, T)〉/max〈Sz〉, near v = 1/3. The ℘(T) data at v = 1/3 probe the neutral spin-flip excitations of a fractional quantum Hall ferromagnet. In addition, the drop in the saturated ℘(v) on either side of v = 1/3 is consistent with an average of ∼0.1 spin-flips per quasihole (or quasiparticle), a value which does not appear to be explicable by the current theoretical understanding of the FQHE near v = 1/3. Below 0.5 K, the spectra also provide evidence that spin-reversed charged excitations of the v = 1/3 ground state are localized over the NMR time scale of ∼40 ms.

Original languageEnglish (US)
Pages (from-to)113-120
Number of pages8
JournalPhysica B: Condensed Matter
StatePublished - Dec 2 1998
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


  • Fractional quantum Hall effect
  • GaAs
  • NMR


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