Competition between fractional quantum Hall liquid and Wigner solid at small fillings: Role of layer thickness and Landau level mixing
Competition between fractional quantum Hall liquid and Wigner solid at small fillings: Role of layer thickness and Landau level mixing
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DOI：
10.1103/physrevresearch.3.013181
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发表时间：
2020-10
影响因子：
4.2
通讯作者：
K. V. Rosales;S. Singh;M. Ma;M. S. Hossain;Y. J. Chung;L. Pfeiffer;K. West;K. Baldwin;M. Shayegan
中科院分区：
文献类型：
--
作者：
K. V. Rosales;S. Singh;M. Ma;M. S. Hossain;Y. J. Chung;L. Pfeiffer;K. West;K. Baldwin;M. Shayegan
二维电子系统（2DES）在非常低的朗道能级填充因子（$\nu$）下，相互作用占主导地位，基态的命运是什么？一种有序的电子排列，即所谓的维格纳晶体，长期以来一直被认为是答案。事实上，正是在寻找难以捉摸的维格纳晶体的过程中，人们发现了一种意想不到的、不可压缩的液态，即分数量子霍尔态（$\nu=1/3$）。了解液体基态和固体基态之间的竞争一直是基础研究的一个活跃领域。在这里，我们报告了一个新的二维系统的实验数据，其中电子被限制在AlAs量子阱中。样品的高质量和大的电子有效质量使我们能够在$\simeq 1/3$和$\simeq 1/5$附近的大范围填充因子范围内确定二维电子的液固相图。这些数据及其与现有理论相图的比较揭示了朗道能级混合和有限电子层厚度在确定主要基态方面的关键作用。
What is the fate of the ground state of a two-dimensional electron system (2DES) at very low Landau level filling factors ($\nu$) where interaction reigns supreme? An ordered array of electrons, the so-called Wigner crystal, has long been believed to be the answer. It was in fact the search for the elusive Wigner crystal that led to the discovery of an unexpected, incompressible liquid state, namely the fractional quantum Hall state at $\nu=1/3$. Understanding the competition between the liquid and solid ground states has since remained an active field of fundamental research. Here we report experimental data for a new two-dimensional system where the electrons are confined to an AlAs quantum well. The exceptionally high quality of the samples and the large electron effective mass allow us to determine the liquid-solid phase diagram for the two-dimensional electrons in a large range of filling factors near $\simeq 1/3$ and $\simeq 1/5$. The data and their comparison with an available theoretical phase diagram reveal the crucial role of Landau level mixing and finite electron layer thickness in determining the prevailing ground states.