Spin-polarization in Fractional Quantum Hall Effect

Spin Peierls Effect in Spin Polarization of Fractional Quantum Hall States

Fractional quantum Hall effect and Wigner crystal of interacting composite fermions.

In two-dimensional electron systems confined to GaAs quantum wells, as a function of either tilting the sample in a magnetic field or increasing density, we observe multiple spin-polarization transitions of the fractional quantum Hall states at filling factors ν=4/5 and 5/7. The number of observed transitions provides evidence that these are fractional quantum Hall states of interacting two-flu...

Clustering in quantum Hall effect: Spin-charge coupling

The effective fractional charges like 17/4 or 19/4 are explained by our angular momentum theory. These fractions do not arise from odd-denominator rule. Due to same spin polarization for both of these along the magnetic field, these states are not the particlehole conjugates. The idea of clustering first introduced in cond-mat/0303309 has been extended to atomic clusters which explain the oscil...

Nonlocal Polarization Feedback in a Fractional Quantum Hall Ferromagnet.

In a quantum Hall ferromagnet, the spin polarization of the two-dimensional electron system can be dynamically transferred to nuclear spins in its vicinity through the hyperfine interaction. The resulting nuclear field typically acts back locally, modifying the local electronic Zeeman energy. Here we report a nonlocal effect arising from the interplay between nuclear polarization and the spatia...

Spin-flip and spin-wave excitations in arbitrarily polarized quantum Hall states

We study spin-flip and spin-wave excitations for arbitrarily polarized quantum Hall states by employing a fermionic Chern-Simons gauge theory in the low Zeeman energy limit. We show that the spin-flip correlation functions do not get renormalized by the fluctuations of Chern-Simons gauge field. As a consequence, the excitations for a given integer quantum Hall state are identical to fractional ...