Dispersive line shape in the vicinity of the ν = 1 quantum Hall state: Coexistence of Knight shifted and unshifted resistively detected NMR responses

Abstract

The frequency splitting between the dip and the peak of the resistively detected nuclear magnetic resonance (RDNMR) dispersive line shape (DLS) has been measured in the quantum Hall effect regime as a function of filling factor, carrier density and nuclear isotope. The splitting increases as the filling factor tends to ν = 1 and is proportional to the hyperfine coupling, similar to the usual Knight shift versus ν-dependence. The peak frequency shifts linearly with magnetic field throughout the studied filling factor range and matches the unshifted substrate signal, detected by classical NMR. Thus, the evolution of the splitting is entirely due to the changing Knight shift of the dip feature. The nuclear spin relaxation time, T1, is extremely long (hours) at precisely the peak frequency. These results are consistent with the local formation of a ν = 2 phase due to the existence of spin singlet D${}^{-}$ complexes.

to be published in Rapid Communication PRB

References in corpus (5)

• Spin Transition in the Half-Filled Landau Level
• Optical absorption to probe the quantum Hall ferromagnet at filling factor $\nu =1$
• NMR Probing Spin Excitations in the Ring-Like Structure of a Two-Subband System
• Knight shift detection using gate-induced decoupling of the hyperfine interaction in quantum Hall edge channels
• Dynamic nuclear polarization induced by breakdown of fractional quantum Hall effect

Cited by in corpus (7)

• First-principles hyperfine tensors for electrons and holes in GaAs and silicon
• Resistively-detected NMR lineshapes in a quasi-one dimensional electron system
• Disorder-induced stabilization of the quantum Hall ferromagnet
• Magnetotransport patterns of collective localization near $\nu =1$ in a high-mobility two-dimensional electron gas
• Role of chiral quantum Hall edge states in nuclear spin polarization
• RD-NMR spectra of the crystal states of the two-dimensional electron gas in a quantizing magnetic field
• Dipole-like dynamical nuclear spin polarization around a quantum point contact