Nano-systems on the Surface of Liquid Helium

利用表面态电子作为探针，利用单电子对液氦表面的操纵，研究了液氦的表面相关现象。构建了可产生低至40μK温度的核退磁低温恒温器，并在^3He-A和^3He-B上测量了Wigner固体的输运性质。我们的数据质量足以讨论超流体He-3的详细结构结构。搭建了旋转低温恒温器，并在其上测量了二维电子在液氦上的输运性质。与我们以前的设备相比，旋转的稳定性得到了极大的提高。由于表面子带之间的跃迁，成功地观察到130 GHz毫米波的吸收降至15 mK，这是液氦单电子量子操纵的基础。毫米波辅助逃逸现象是下一个要研究的目标。我们制备了多个纳米间隙电极系统来研究表面态电子在氦膜上的输运。这是实现单电子操纵的基础关键技术。然而，我们观察到，在金属表面吸附的氦膜上的大多数电子都是局域的，对传导没有贡献。下一步，应使用毛细管凝聚氦通道作为衬底。我们将在未来实现单电子操纵。

We studied the surface related phenomena of liquid helium by using surface state electrons as a probe and the manipulation of single electrons on a liquid helium surface. A nuclear demagnetization cryostat is constructed, which can produce temperatures as low as 40μK and the transport properties of the Wigner solid is measured on both ^3He-A and ^3He-B. The quality of our data is good enough to discuss the detailed textural structure of superfluid He-3. In addition, the rotating cryostat is constructed and on which the transport properties of 2D electrons on liquid helium is measured. The stability of rotation is improved drastically compared to our previous apparatus. Absorption of millimeter wave of 130 GHz because of the transition between the surface sub-bands is observed successfully down to 15 mK The knowledge is a basis of the quantum manipulation of single electrons on liquid helium. Millimeter-wave-assisted escape phenomena is the next target to study. We prepared a number of nano-gapped electrodes system to study the transport of surface state electrons on a helium film. This is a fundamental key technology to realize single electron manipulation. We observed, however, that the most of electrons on a helium film adsorbed on a metal surface are localized and do not contribute to the conduction. In the next step a capillary condensed helium channel should be used as a substrate. We are going to realize the single electron manipulation in the future.