We report a resistively detected nuclear magnetic resonance (RDNMR) measurement in a GaAs-based quantum point contact in the quantum Hall breakdown regime. We focus on the detection of the As75 RDNMR signal at different perpendicular magnetic fields in the presence of electrons occupying the lowest Landau level. We confirm successful RDNMR detection down to B=1.25T (B=3.5T) using a high-mobility (low-mobility) device. All the RDNMR signals exhibit a threefold spectra attributed to electric quadrupole interaction. We find that the separation between the central transition and its satellite, Δf≈20kHz, remains unaffected by magnetic-field variation. Interestingly, the central NMR linewidths vary with the field strength. Above B=3T, the linewidth tends to saturate around 13 kHz. Below B=3T, the linewidth decreases in proportion with field and approaches a lower limit of 1 kHz corresponding to the GaAs nuclear dipole interaction as the field decreases to B=1.25T.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics