Melting phase diagram of bubble phases in high Landau levels
Melting phase diagram of bubble phases in high Landau levels
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DOI：
10.1103/physrevb.104.l121110
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发表时间：
2021-08
影响因子：
3.7
通讯作者：
K. Villegas Rosales;S. Singh;H. Deng;Y. Chung;L. Pfeiffer;K. West;K. Baldwin;M. Shayegan
中科院分区：
文献类型：
--
作者：
K. Villegas Rosales;S. Singh;H. Deng;Y. Chung;L. Pfeiffer;K. West;K. Baldwin;M. Shayegan
低无序二维电子系统（2DES）在大垂直磁场作用下冷却至极低温度，为多体量子相的研究提供了丰富的平台。磁场熄灭了电子的动能，并将能量量化为一组朗道能级，从而使库仑相互作用占主导地位。在激发态朗道能级中，短期和长期相互作用之间的精细相互作用稳定了气泡相，即每单元细胞具有一个以上电子的维格纳晶体。在这里，我们展示了气泡相的屏蔽特性，通过一种简单的电容技术来探测，其中2DES放置在顶部和底部栅极之间，并测量穿透2DES的电场。在非常低的温度下形成的气泡由于受到残余无序电位的束缚，对电场的屏蔽效果很差，从而使一个大的电场到达顶部栅极。随着温度的升高，穿透电场减小，令人惊讶的是，在与气泡相熔化温度一致的温度处，穿透电场表现出明显的最小值。当朗道液面填充因子4≤ν≤5时，我们推导出气泡向液相转变的定量相图。
A low-disorder, two-dimensional electron system (2DES) subjected to a large perpendicular magnetic field and cooled to very low temperatures provides a rich platform for studies of many-body quantum phases. The magnetic field quenches the electrons’ kinetic energy and quantizes the energy into a set of Landau levels, allowing the Coulomb interaction to dominate. In excited Landau levels, the fine interplay between shortand long-range interactions stabilizes bubble phases, Wigner crystals with more than one electron per unit cell. Here we present the screening properties of bubble phases, probed via a simple capacitance technique where the 2DES is placed between a top and a bottom gate and the electric field penetrating through the 2DES is measured. The bubbles formed at very low temperatures screen the electric field poorly as they are pinned by the residual disorder potential, allowing a large electric field to reach the top gate. As the temperature is increased, the penetrating electric field decreases and, surprisingly, exhibits a pronounced minimum at a temperature that appears to coincide with the melting temperature of the bubble phase. We deduce a quantitative phase diagram for the transition from bubble to liquid phases for Landau level filling factors 4 ≤ ν ≤ 5.