  We study nuclear relaxation in the presence of localized electrons in a
two-dimensional electron gas in a disordered delta-doped semiconductor
heterostructure and show that this method can reliably probe their magnetic
interactions and possible long-range order. In contrast, we argue that
transport measurements, the commonly employed tool, may not sometimes
distinguish between spatial disorder and long-range order. We illustrate the
utility of using the nuclear relaxation method to detect long-range order by
analyzing a recent proposal made on the basis of transport measurements, on the
spontaneous formation of a two-dimensional Kondo lattice in a 2D electron gas
in a heterostructure.
