Electrically controlled nuclear spin polarization and relaxation by quantum-Hall states.
We study interactions between electrons and nuclear spins by using the resistance ( Rxx) peak which develops near the Landau-level filling factor nu = 2/3 as a probe. Temporarily tuning nu to a different value, nu(temp), with a gate demonstrates that the Rxx peak regenerates even after complete depletion ( nu(temp) = 0), while it rapidly relaxes on either side of nu(temp) = 1. This indicates that the nu = 2/3 domain morphology is memorized by the nuclear spins which can be rapidly depolarized by Skyrmions. An additional enhancement in the nuclear spin relaxation around nu = 1/2 and 3/2 suggests a Fermi sea of partially polarized composite fermions.
Hashimoto
K
K
NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan. hashi@will.brl.ntt.co.jp
Muraki
K
K
Saku
T
T
Hirayama
Y
Y