Long-distance correlation-length effects and hydrodynamics of He-4 films in a Corbino geometry

Article

关键词: KOSTERLITZ-THOULESS TRANSITION;    SUPERFLUID TRANSITION;    NUCLEPORE;    FRACTION;    BEHAVIOR;    DENSITY;   

DOI  :  10.1103/PhysRevB.94.094520

来源: SCIE

【 摘 要 】

Previous measurements of the superfluid density rho(s) and specific heat for He-4 have identified effects that are manifest at distances much larger than the correlation length xi(3D) [Perron et al., Nat. Phys. 6, 499 (2010); Perron and Gasparini, Phys. Rev. Lett. 109, 035302 (2012); Perron et al., Phys. Rev. B 87, 094507 (2013)]. We report here measurements of the superfluid density which are designed to explore this phenomenon further. We determine the superfluid fraction rho(s)/rho from the resonance of 34-nm films of varying widths 4 <= W <= 100 mu m. The films are formed across a Corbino ring separating two chambers where a thicker 268-nm film is formed. This arrangement is realized using lithography and direct Si-wafer bonding. We identify two effects in the behavior of rho(s)/rho: one is hydrodynamic, for which we present an analysis, and the other is a correlation-length effect which manifests as a shift in the transition temperature T-c relative to that of a uniform 34-nm film uninfluenced by proximity effects. We find that one can collapse both rho(s)/rho and the quality factor of the resonance onto universal curves by shifting T-c as Delta T-c similar to W-nu. This scaling is a surprising result on two counts: it involves a very large length scale W relative to the magnitude of xi(3D) and the dependence on W is not what is expected from correlation-length finite-size scaling which would predict Delta T-c similar to W-1/nu.

【 授权许可】

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