Resistively detected NMR with dispersive lineshape in single InSb quantum wells

We present a DC measurement of resistively detected NMR (RDNMR) in a single InSb/AlInSb quantum well. Dynamic nuclear polarization has been demonstrated around the resistance spike, which is the signature of the pseudospin quantum Hall ferromagnet at the filling factor of two. The RDNMR signals with dispersive lineshape occur on each side of the spike, but show the shape inversion. The dispersionlike lineshape is found to be independent of measurement conditions (current intensity, temperature, and RF power), provided the polarized nuclei are in equilibrium.