Effect of the Nuclear Hyperfine Field on the 2D Electron Conductivity in the Quantum Hall Regime Page: 1 of 9
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JETP LETERS VOLUME 69, NUMBER 1 10 JANUARY 1999
Effect of the nuclear hyperfine field on the 2D electron
conductivity in the quantum Hall regime
S. A. Vitkalov
Chemistry Department and National High Magnetic Field Laboratory, University of
Florida, Gainesville, Florida 32611-7200 USA;
P. N. Lebedev Physical Institute, Russian Academy of Sciences, 117924 Moscow, Russia
C. R. Bowers
Chemistry Department and National High Magnetic Field Laboratory, University of
Florida, Gainesville, Florida 32611-7200 USA
J. A. Simmons and J. L. Reno
Sandia National Laboratories, Albuquerque, NM 87185-1415
(Submitted 19 November 1998; resubmitted 2 December 1998)
Pis'ma Zh. Eksp. Teor. Fiz. 69, No. 1, 58-63 (10 January 1999)
The effect of the nuclear hyperfine interaction on the dc conductivity of
2D electrons under quantum Hall effect conditions at filling factor v=1
is observed for the first time. The local hyperfine field enhanced by
dynamic nuclear polarization is monitored via the Overhauser shift of
the 2D conduction electron spin resonance in AIGaAs/GaAs
multiquantum-well samples. The experimentally observed change in
the dc conductivity resulting from dynamic nuclear polarization is in
agreement with a thermal activation model incorporating the Zeeman
energy change due to the hyperfine interaction. The relaxation decay
time of the dc conductivity is, within experimental error, the same as
the relaxation time of the nuclear spin polarization determined from the
Overhauser shift. These findings unequivocally establish the nuclear
spin origins of the observed conductivity change. 1999 American
Institute of Physics. [S0021-3640(99)01201-3]
PACS numbers: 73.40.Hm, 72.15.-v, 73.20.Dx
In conductors and superconductors, fluctuations of the hyperfine contact interaction
usually provide the dominant mechanism for nuclear spin relaxation at low
temperatures.1.2 These relaxation times are closely related to the electronic structure and
dynamics in these materials. In recent years it has been recognized that the hyperfine
interaction can serve as a powerful tool in studies of 2D conducting electron systems.
Several notable applications include the quantum Hall effect (QHE)3 and quantum
computation.4 However, studies of the effect of electron-nuclear spin interactions on the
electronic transport are very rare. In nonmagnetic metals the spin-spin interaction be-
tween electrons and nuclei is theoretically predicted to produce a strongly magnetic-field
and temperature dependent contribution to the resistivity.5 The contribution of the hyper-
fine interaction to magnetotransport quantum oscillations of the resistivity has been ob-0021-3640/99/69(1)/7/$15.00 64 1999 American Institute of Physics
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Vitkalov, S.A.; Bowers, C.R.; Simmons, Jerry A. & Reno, John L. Effect of the Nuclear Hyperfine Field on the 2D Electron Conductivity in the Quantum Hall Regime, article, July 13, 2000; Albuquerque, New Mexico. (https://digital.library.unt.edu/ark:/67531/metadc706819/m1/1/?rotate=270: accessed April 24, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.