Quantum Hall transitions in field-induced spin density systems

Field-induced spin density wave (FISDW) systems exhibit coexistence phases between well-defined Quantum Hall plateaux phases with even integers 2N and 2N′. We show that a disordered coexistence region accounts for the observed peaks in the longitudinal reisitivity as the field varies between plateaux. It also results in a random spin mixing which yields two energy-split extended states. The longitudinal resistance is expected to show two peaks with a temperature (T) dependent width ∼Tκ. The peak width should saturate below the non-nesting interlayer coupling of ≈40 mK.