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arXiv 1503.07775cond-mat.mes-hall
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Corbino几何中的第二朗道能级分数量子霍尔效应

Second Landau Level Fractional Quantum Hall Effects in the Corbino Geometry

B. A. Schmidt, K. Bennaceur, S. Bilodeau, G. Gervais, L. N. Pfeiffer, K. W. West

摘要:

对于某些测量,Corbino几何形状比Hall和van der Pauw几何形状具有明显的优势,因为它提供了体2DEG的直接探测,而没有由于边缘效应而引起的复杂性。这在使得能够经由体热力学测量检测5/2分数量子霍尔态的非阿贝尔熵中可能是重要的。我们报告的成功制造和测量的Corbino几何样品在超高迁移率GaAs异质结构,重点是在第二和更高的朗道能级的运输。特别是,我们报告的分数量子霍尔态的激活能隙,排除了所有的边缘效应,并外推的电导率前因子从阿克里欧斯适合。我们的研究结果表明,在第二朗道水平激活运输仍然知之甚少。这种Corbino设备的开发打开了使用其他几何形状中不可能的技术来研究5/2状态的可能性。

英文摘要:

For certain measurements, the Corbino geometry has a distinct advantage over the Hall and van der Pauw geometries, in that it provides a direct probe of the bulk 2DEG without complications due to edge effects. This may be important in enabling detection of the non-Abelian entropy of the 5/2 fractional quantum Hall state via bulk thermodynamic measurements. We report the successful fabrication and measurement of a Corbino-geometry sample in an ultra-high mobility GaAs heterostructure, with a focus on transport in the second and higher Landau levels. In particular, we report activation energy gaps of fractional quantum Hall states, with all edge effects ruled out, and extrapolate the conductivity prefactor from the Arrhenius fits. Our results show that activated transport in the second Landau level remains poorly understood. The development of this Corbino device opens the possibility to study the bulk of the 5/2 state using techniques not possible in other geometries.

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