Spin stiffness of a Fermi liquid in the ν = 1 quantum Hall regime
Anomalous behavior of spin stiffness is revealed in ZnO-based two-dimensional electron systems (2DESs)
with strong Coulomb interaction and Wigner-Seitz parameter r_s > 6. The spin stiffness is extracted directly from
the quadratic k-dispersion of spin excitons at ν = 1 probed by inelastic light scattering. The resulting values are
found to be dramatically rescaled compared to the case of weakly interacting 2DESs—spin stiffness turned out
to be of the order of the cyclotron energy with the effective mass of Fermi-liquid quasiparticles. This result is
also confirmed by the exact diagonalization simulations.