NMR Measurements of GaAs/AlGaAs Multiple Quantum Wells Heterostructures around Landau Level Filling Factor ν = 1
Abstract
The spin dynamics and spin polarization of two-dimensional electrons have been investigated in the quantum Hall effect regime using a standard nuclear magnetic resonance (NMR) technique. Low temperature measurements of gallium spin-lattice relaxation rate 1/T1 (reflecting the electron spin dynamics) and hyperfine shift KS (measuring the electron spin polarization) were performed on two GaAs/AlGaAs multiple-quantum-well heterostructures. In the vicinity of Landau level filling factor ν=1, KS displays a peak indicative of the presence of Skyrmions in the electronic ground-state( S.L. Sondhi et al.), Phys. Rev. B 47, 16419 (1993). ^,( S.E. Barrett et al.), Phys. Rev. Lett. 74, 5112 (1995). . We report the study of the temperature dependence of this peak, as well as its dependence on the total magnetic field (with the sample tilted to maintain the ν=1 condition). As the observed 1/T1 and KS results do not fit consistently the theoretical description of the ν=1 quantum Hall effect state( R. Côté et al.), Phys. Rev. Lett. 78, 4825 (1997). , we discuss possible explanations for these discrepancies.
- Publication:
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APS March Meeting Abstracts
- Pub Date:
- March 2000
- Bibcode:
- 2000APS..MARG17001M