Smet, J. H. and Deutschmann, R. A. and Ertl, F. and Wegscheider, Werner and Abstreiter, Gerhard and Klitzing, Klaus von
Anomalous-Filling-Factor-Dependent Nuclear-Spin Polarization in a 2D Electron System.
Physical Review Letters 92 (8), 086802.
Spin-related electronic phase transitions in the fractional quantum Hall regime are accompanied by a large change in resistance. Combined with their sensitivity to spin orientation of nuclei residing in the same plane as the 2D electrons, they offer a convenient electrical probe to carry out nuclear magnetometry. Despite conditions which should allow both electronic and nuclear-spin subsystems to approach thermodynamic equilibrium, we uncover for the nuclei a remarkable and strongly electronic filling-factor-dependent deviation from the anticipated thermal nuclear-spin polarization.