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arXiv · 1511.06643

Surface Acoustic Waves Probe of the Spin Phase Transition at $\nu$=2/3 in n-GaAs/AlGaAs structure

I. L. Drichko·I. Yu. Smirnov·A. V. Suslov·L. N. Pfeiffer·K. W. West
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Abstract

High frequency (ac) conductivity in the single quantum well AlGaAs/GaAs/AlGaAs with high mobility was investigated by contactless acoustic methods in the fractional quantum Hall effect regime in perpendicular and tilted magnetic fields. We studied the dependence of ac conductivity $\sigma^{ac}=\sigma_1 - i\sigma_2$ on both the temperature and magnetic field tilt angle. Tilting the magnetic field relative to the sample surface enabled us to change the position of the conductivity oscillation minimum at $\nu$=2/3. We measured the temperature dependence of ac conductivity for each tilt angle and for the 2/3 state we calculated the activation energy $\Delta E$ which was derived by constructing the Arrhenius plot ln $\sigma_1$ against 1/$T$. Analyzing behavior of the activation energy in total magnetic field for the filling factor 2/3 we observed a distinct minimum which can be interpreted as the spin unpolarized-polarized phase transition.

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I. L. Drichko, I. Yu. Smirnov, A. V. Suslov, L. N. Pfeiffer, K. W. West. 2015-11-20. Surface Acoustic Waves Probe of the Spin Phase Transition at $\nu$=2/3 in n-GaAs/AlGaAs structure. https://doi.org/10.1088/1742-6596/568/5/052031

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