  Detection and characterization of a different type of topological
excitations, namely the domain wall (DW) skyrmion, has received increasing
attention because the DW is ubiquitous from condensed matter to particle
physics and cosmology. Here we present experimental evidence for the DW
skyrmion as the ground state stabilized by long-range Coulomb interactions in a
quantum Hall ferromagnet. We develop an alternative approach using nonlocal
resistance measurements together with a local NMR probe to measure the effect
of low-current-induced dynamic nuclear polarization and thus to characterize
the DW under equilibrium conditions. The dependence of nuclear spin relaxation
in the DW on temperature, filling factor, quasiparticle localization, and
effective magnetic fields allows us to interpret this ground state and its
possible phase transitions in terms of Wigner solids of the DW skyrmion. These
results demonstrate the importance of studying the intrinsic properties of
quantum states that has been largely overlooked.
