Optically Induced Dynamic Nuclear Spin Polarization in Quantum Hall Regime Observed by a Time-Resolved Kerr Rotation

Abstract

The dynamics between electron and nuclear spins in quantum Hall regime is investigated by a time-resolved Kerr rotation (TRKR) spectroscopy carried down in tilted-field geometry. The spin-flip energy varies almost linearly with the applied magnetic field under the nuclear spin depolarizing radio frequency field and the helicity modulation of circularly polarized pump, while the spin-flip energy obtained under a circularly polarized pump deviates from linearly behavior. This deviation is ascribed to the Overhauser shift due to dynamic nuclear spin polarization (DNP). The DNP depends markedly on the filling factor and present peaks at even filling factors. These results can be well explained by a simple model based on the detailed balance between electron and nuclear spins.

Simultaneous measurement of resistively and optically detected nuclear magnetic resonance in theν=2/3fractional quantum Hall regime

“…For instance, the different size of skyrmion has been observed and argued [1][2][3][4]. The optical nuclear polarization observed in optical method is much larger than that in conventional and resistive methods [4][5][6][7][8][9]. The case of the electron spin polarization at Landau level filling factor ν = 5/2 is more complicated; the different experimental methods show the fully polarized state, unpolarized system, and partially polarized domains [10][11][12][13][14][15][16][17].…”