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arXiv 2104.02590cond-mat.mes-hall
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分数量子霍尔效应能隙:电子层厚度的作用

Fractional quantum Hall effect energy gap: role of electron layer thickness

K. A. Villegas Rosales, P. T. Madathil, Y. J. Chung, L. N. Pfeiffer, K. W. West, K. W. Baldwin, M. Shayegan

摘要:

分数量子霍尔效应是二维电子相互作用系统的典型表现。爱因斯坦最基本的特征之一是将不可压缩的基态与其激发态分开的能隙。然而,尽管近四十年的研究,理论计算和实验测量的能隙之间的定量协议是缺乏的。在这里,我们报告的测量的能隙和可用的理论计算,考虑到有限层厚度和朗道能级混合的作用之间的定量比较。我们的系统的实验研究的ECOHE能隙使用非常高品质的二维电子系统局限于GaAs量子阱与不同的阱宽。所有能隙的测量值都低于计算值,但随着电子层厚度的增加,实验值与计算值的接近。占无序的作用,在现象学的方式,我们发现测量的能隙是在合理的定量计算一致,虽然仍然存在一些差异。

英文摘要:

The fractional quantum Hall effect (FQHE) stands as a quintessential manifestation of an interacting two-dimensional electron system. One of FQHE's most fundamental characteristics is the energy gap separating the incompressible ground state from its excitations. Yet, despite nearly four decades of investigations, a quantitative agreement between the theoretically calculated and experimentally measured energy gaps is lacking. Here we report a quantitative comparison between the measured energy gaps and the available theoretical calculations that take into account the role of finite layer thickness and Landau level mixing. Our systematic experimental study of the FQHE energy gaps uses very high-quality two-dimensional electron systems confined to GaAs quantum wells with varying well widths. All the measured energy gaps fall bellow the calculations, but as the electron layer thickness increases, the results of experiments and calculations come closer. Accounting for the role of disorder in a phenomenological manner, we find the measured energy gaps to be in reasonable quantitative agreement with calculations, although some discrepancies remain.

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