Entropy of solid He4: the possible role of a dislocation glass

Abstract

Solid He4 is viewed as a nearly perfect Debye solid. Yet, recent calorimetry indicates that its low-temperature specific heat has both cubic and linear contributions. These features appear in the same temperature range ($T\sim 200$ mK) where measurements of the torsional oscillator period suggest a supersolid transition. We analyze the specific heat to compare the measured with the estimated entropy for a proposed supersolid transition with 1% superfluid fraction. We find that the experimental entropy is substantially less than the calculated entropy. We suggest that the low-temperature linear term in the specific heat is due to a glassy state that develops at low temperatures and is caused by a distribution of tunneling systems in the crystal. It is proposed that small scale dislocation loops produce those tunneling systems. We argue that the reported mass decoupling is consistent with an increase in the oscillator frequency as expected for a glass-like transition.

4 pages latex file with 4 eps figure files

References in corpus (3)

• Superglass Phase of Helium-four
• Supersolid Helium at High Pressure
• Melting curve of ${}^4$He: no sign of the supersolid transition down to 10 mK

Cited by in corpus (28)

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• What makes a crystal supersolid ?
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• Dual gauge field theory of quantum liquid crystals in three dimensions
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• Theory of the superglass phase
• Thermal History of Solid 4He Under Oscillation
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• Absence of Pressure-Driven Supersolid Flow at Low Frequency
• Minimal Model for Disorder-induced Missing Moment of Inertia in Solid ${}^4$He
• Mesoscopic Coulomb Supersolid
• The glassy response of solid He-4 to torsional oscillations
• Two-level systems and mass deficit in quantum solids
• Absence of low temperature anomaly on the melting curve of ${}^4$He
• A glassy contribution to the heat capacity of hcp ${}^4$He solids
• A glass anomaly in the shear modulus of solid ${}^4$He
• Torsional oscillators and the entropy dilemma of putative supersolid He-4
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• Fast Diffusion Process in Quenched hcp Dilute Solid ${}^3$He-${}^4$He Mixture
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• Shear modulus in viscoelastic solid ${}^4$He
• A search for disordered (glassy) phase in solid 3He deformed in situ
• A tentative replica theory of glassy Helium 4
• NMR Study of Disordered Inclusions in the Quenched Solid Helium
• Defects and glassy dynamics in solid He-4: Perspectives and current status
• Off-diagonal Long-Range Order and Supersolidity in a Quantum Solid with Vacancies
• The role of glass dynamics in the anomaly of the dielectric function of solid helium