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 Title: Superfluid helium on solid hydrogen Author(s): Chen, Ming-Tang Doctoral Committee Chair(s): Mochel, J.M. Department / Program: Physics Discipline: Physics Degree Granting Institution: University of Illinois at Urbana-Champaign Degree: Ph.D. Genre: Dissertation Subject(s): Physics, Condensed Matter Abstract: We measure the third sound velocity of superfluid helium films as functions of temperature and film coverage on H$\sb2,$ D$\sb2,$ and Ar substrates. A new phase of superfluid is discovered on the weak-binding H$\sb2$ substrate. We observe, in addition to third sound, a new surface mode of wave propagation in superfluid films. On a D$\sb2$ substrate, we observe a similar phase diagram as on H$\sb2,$ though only the third sound mode is seen.The measurement of the third sound velocity as a function of coverage in the T = 0K limit is in close agreement with the results from two independent theoretical models. The measured third sound velocity is analyzed to yield a Van der Waals constant and an inert layer for $\sp4$He on H$\sb2$ of 13.1 $\pm$ 8 K $\cdot$ Layer$\sp3$ and 0.34 $\pm$ 0.09 Layers, respectively. These values are compared to our previous results, and the results from other groups. Issue Date: 1993 Type: Text Language: English URI: http://hdl.handle.net/2142/23036 Rights Information: Copyright 1993 Chen, Ming-Tang Date Available in IDEALS: 2011-05-07 Identifier in Online Catalog: AAI9411583 OCLC Identifier: (UMI)AAI9411583
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