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arXiv · 0709.1265

NMR Study of Large Skyrmions in Al_{0.13}Ga_{0.87}As Quantum Wells

V. F. Mitrović·M. Horvatić·C. Berthier·S. A. Lyon·M. Shayegan
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Abstract

A nuclear magnetic resonance (NMR) study is reported of multiple (30) Al$_{0.13}$Ga$_{0.87}$As quantum well (QW) sample near the Landau level filling factor $ν=1$. In these Al$_{0.13}$Ga$_{0.87}$As QWs the effective $g$ factor is nearly zero. This can lead to two effects: vanishing electronic polarization $(P)$ and skyrmionic excitations composed of a huge number of spins. As small $P$ 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 $T_{2}^{-1}$ rate.

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V. F. Mitrović, M. Horvatić, C. Berthier, S. A. Lyon, M. Shayegan. 2007-09-09. NMR Study of Large Skyrmions in Al_{0.13}Ga_{0.87}As Quantum Wells. https://doi.org/10.1103/physrevb.76.115335

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