We observe variation in the resistively-detected nuclear magnetic resonance (RDNMR) lineshapes in quantum Hall breakdown. The breakdown is locally occurred in a gate-defined quantum point contact (QPC) region. Of particular interest is the observation of a dispersive lineshape occured when the bulk 2D electron gas (2DEG) is set to νb=2 and the QPC filling factor to the vicinity of νQPC=1, strikingly resemble the dispersive lineshape observed on a 2D quantum Hall state. This previously unobserved lineshape in a QPC points to simultaneous occurrence of two hyperfine-mediated spin flip-flop processes within the QPC. Those events give rise to two different sets of nuclei polarized in the opposite direction and positioned at a separate region with different degree of electronic polarizations.
@article{arxiv.1703.03520,
title = {Resistively-detected NMR lineshapes in a quasi-one dimensional electron system},
author = {M. H. Fauzi and A. Singha and M. F. Sahdan and M. Takahashi and K. Sato and K. Nagase and B. Muralidharan and Y. Hirayama},
journal= {arXiv preprint arXiv:1703.03520},
year = {2017}
}