Studies with Liquid Helium Films

液氦薄膜研究

• 批准号: 9422208
• 负责人: Robert Hallock
• 金额: $ 43.88万
• 依托单位: University of Massachusetts Amherst
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-01-01 至 1998-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9422208&HistoricalAwards=false
• 关键词: Studies; Liquid; Helium; Films

9422208 Hallock This proposal has four major points of emphasis: (1) To continue nuclear magnetic resonance and third sound studies of the helium3- helium4 mixture film system, specifically to study the strong effect on the helium3 of the helium4 film thickness with analogy with metal insulator transitions in 2D electron systems, and to search for transitions to new superfluid helium3 behavior which have been predicted. (2) To continue experiments with helium films on alkali metal surfaces in order to study wetting phenomena. (3) To study in more detail capillary condensation and avalanche phenomena with helium in porous materials. (4) To continue to study helium films patterned substrates in one and two dimensions. (5) To study linear and nonlinear behavior of third sound pulses in collision. The techniques used will include nuclear magnetic resonance, bolometric and quartz resonance and capacitance measurements. These experiments will develop our understanding of the helium film system and have impact more widely in Condensed Matter Physics. %%% This program will undertake a fundamental investigations of thin films of liquid helium which form on surfaces at extremely low temperatures. These films, which can be a few atoms thick, have remarkable properties and allow the study of physics in two dimensions which have implications for physics in other areas of Condensed Matter Physics. The emphasis will be on studies of mixtures of the two types of helium in which new types of superfluid behavior will be searched for. Analogies with metal insulator transitions will be explored. Peculiar wetting behavior between helium and certain unusual surfaces will be investigated. Capillary condensation and other phenomena in porous materials flooded with helium will be studied. The program will also investigate the interaction between microscopic waves on helium films and between such waves and th e surface on which they reside. ***

9422208哈洛克这个建议有四个主要的重点：（1）继续氦3-氦4混合物膜系统的核磁共振和第三声研究，特别是研究氦4膜厚度对氦3的强烈影响，并与2D电子系统中的金属绝缘体跃迁进行类比，并寻找已被预测的新的超流体氦3行为的转变。(2)继续进行碱金属表面氦膜的实验，以研究润湿现象。(3)详细研究氦在多孔材料中的毛细凝聚和雪崩现象。(4)继续研究一维和二维的氦膜图案化衬底。 (5)研究第三声脉冲的线性和非线性行为 碰撞。所使用的技术将包括核磁共振、测辐射热和石英共振以及电容 测量. 这些实验 将发展我们对氦膜系统的理解，并在凝聚态物理学中产生更广泛的影响。 %此程序 将对极低温度下在表面形成的液氦薄膜进行基础研究。 这些薄膜可以是几个原子厚，具有显着的特性，并允许在二维空间中研究物理学，这对凝聚态物理学的其他领域具有影响。重点将放在研究这两种氦的混合物上，在这种混合物中将寻找新的超流体行为。 将探讨与金属绝缘体过渡的类比。氦和某些不寻常的表面之间的特殊润湿行为将被调查。将研究充满氦气的多孔材料中的毛细凝聚和其他现象。该计划还将研究氦膜上的微观波之间的相互作用，以及这些波与它们所驻留的表面之间的相互作用。 ***