Abstract
A nuclear magnetic resonance (NMR) study is reported of multiple (30) quantum well (QW) sample near the Landau level filling factor . In these QWs the effective factor is nearly zero. This can lead to two effects: vanishing electronic polarization and skyrmionic excitations composed of a huge number of spins. As small values cause an overlap of the NMR signals from the QW and barriers, a special technique was employed to allow these two signals to be distinguished. The QW signal corresponds to a small, negative, and very broad distribution of spin polarization that exhibits thermally induced depolarization. Such a distribution can be attributed to sample inhomogeneities and/or to large skyrmions, the latter possibility being favored by observation of a very fast rate.
- Received 25 May 2007
DOI:https://doi.org/10.1103/PhysRevB.76.115335
©2007 American Physical Society