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arXiv · 1204.0560

Spin Polarization of the 12/5 Fractional Quantum Hall Effect

Chi Zhang·Chao Huan·J. S. Xia·N. S. Sullivan·W. Pan·K. W. Baldwin·K. W. West·L. N. Pfeiffer·D. C. Tsui
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Abstract

We have carried out tilt magnetic field (B) studies of the \nu=12/5 fractional quantum Hall state in an ultra-high quality GaAs quantum well specimen. Its diagonal magneto-resistance Rxx shows a non-monotonic dependence on tilt angle (\theta). It first increases sharply with increasing \theta, reaches a maximal value of ~ 70 ohms at \theta ~ 14^o, and then decreases at higher tilt angles. Correlated with this dependence of Rxx on \theta, the 12/5 activation energy (\Delta_{12/5}) also shows a non-monotonic tilt dependence. \Delta_{12/5} first decreases with increasing \theta. Around \theta = 14^{o}, \Delta_{12/5} disappears as Rxx becomes non-activated. With further increasing tilt angles, \Delta_{12/5} reemerges and increases with \theta. This tilt B dependence at \nu=12/5 is strikingly different from that of the well-documented 5/2 state and calls for more investigations on the nature of its ground state.

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Chi Zhang, Chao Huan, J. S. Xia, N. S. Sullivan, W. Pan, K. W. Baldwin, K. W. West, L. N. Pfeiffer, D. C. Tsui. 2012-04-02. Spin Polarization of the 12/5 Fractional Quantum Hall Effect. https://arxiv.org/abs/1204.0560

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