Levitin Lev V, van der Vliet Harriet, Theisen Terje, Dimitriadis Stefanos, Lucas Marijn, Corcoles Antonio D, Nyéki Ján, Casey Andrew J, Creeth Graham, Farrer Ian, Ritchie David A, Nicholls James T, Saunders John
Department of Physics, Royal Holloway, University of London, Egham, TW20 0EX, UK.
Oxford Instruments Nanoscience, Abingdon, Oxfordshire, OX13 5QX, UK.
Nat Commun. 2022 Feb 3;13(1):667. doi: 10.1038/s41467-022-28222-x.
Two-dimensional electron gases (2DEGs) with high mobility, engineered in semiconductor heterostructures host a variety of ordered phases arising from strong correlations, which emerge at sufficiently low temperatures. The 2DEG can be further controlled by surface gates to create quasi-one dimensional systems, with potential spintronic applications. Here we address the long-standing challenge of cooling such electrons to below 1 mK, potentially important for identification of topological phases and spin correlated states. The 2DEG device was immersed in liquid He, cooled by the nuclear adiabatic demagnetization of copper. The temperature of the 2D electrons was inferred from the electronic noise in a gold wire, connected to the 2DEG by a metallic ohmic contact. With effective screening and filtering, we demonstrate a temperature of 0.9 ± 0.1 mK, with scope for significant further improvement. This platform is a key technological step, paving the way to observing new quantum phenomena, and developing new generations of nanoelectronic devices exploiting correlated electron states.
在半导体异质结构中设计的具有高迁移率的二维电子气（2DEG），在足够低的温度下会呈现出由强关联产生的各种有序相。二维电子气可通过表面栅极进一步控制，以创建具有潜在自旋电子学应用的准一维系统。在这里，我们解决了将此类电子冷却至1 mK以下这一长期存在的挑战，这对于识别拓扑相和自旋相关态可能具有重要意义。二维电子气器件被浸入液氦中，并通过铜的核绝热去磁进行冷却。二维电子的温度是通过一根金线中的电子噪声推断出来的，该金线通过金属欧姆接触与二维电子气相连。通过有效的屏蔽和滤波，我们展示了0.9±0.1 mK的温度，并且有进一步显著改进的空间。这个平台是关键的技术步骤，为观察新的量子现象以及开发利用相关电子态的新一代纳米电子器件铺平了道路。
