Torsional oscillator studies for possible supersolidity in two-dimensional 4He solid

Y. Shibayama, H. Fukuyama, Keiya Shirahama

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

The origin of "supersolidity" of solid 4He, which was reported by Kim and Chan, has not yet been clarified. Although Bose-Einstein condensation of zero-point vacancies (ZPVs) was initially considered to be a possible origin, recent studies imply that crystal imperfections in the solid samples are strongly associated with the observed supersolid behaviors. In two-dimensional (2D) 3He system on graphite, on the other hand, a novel phase due to quantum hopping of ZPVs has been found. This suggests that ZPVs form also in 2D 4He solid systems and their quantum hopping results in superfluidity of ZPVs, namely, supersolidity. In order to search for the possible 2D supersolid state, we perform torsional oscillator studies for 4He films adsorbed on graphite. At the 4He coverage of 18.7 nm-2 a positive frequency shift was observed below 300 mK. The size of the shift decreases with increasing the oscillation velocity. This behavior closely resembles to the supersolid behavior of bulk solid 4He.

Original languageEnglish
Article number032096
JournalJournal of Physics: Conference Series
Volume150
Issue number3
DOIs
Publication statusPublished - 2009

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oscillators
graphite
superfluidity
frequency shift
condensation
oscillations
shift
defects
crystals

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Torsional oscillator studies for possible supersolidity in two-dimensional 4He solid. / Shibayama, Y.; Fukuyama, H.; Shirahama, Keiya.

In: Journal of Physics: Conference Series, Vol. 150, No. 3, 032096, 2009.

Research output: Contribution to journalArticle

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