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Elementary excitations in solid and liquid He-4 at the melting pressure.

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Elementary excitations in solid and liquid He-4 at the melting pressure. / Todoshchenko, I. A.; Alles, H.; Junes, H. J. et al.
In: Journal of Low Temperature Physics, Vol. 150, No. 3-4, 02.2008, p. 258-266.

Research output: Contribution to Journal/MagazineJournal articlepeer-review

Harvard

Todoshchenko, IA, Alles, H, Junes, HJ, Manninen, MS, Parshin, AY & Tsepelin, V 2008, 'Elementary excitations in solid and liquid He-4 at the melting pressure.', Journal of Low Temperature Physics, vol. 150, no. 3-4, pp. 258-266. https://doi.org/10.1007/s10909-007-9544-1

APA

Todoshchenko, I. A., Alles, H., Junes, H. J., Manninen, M. S., Parshin, A. Y., & Tsepelin, V. (2008). Elementary excitations in solid and liquid He-4 at the melting pressure. Journal of Low Temperature Physics, 150(3-4), 258-266. https://doi.org/10.1007/s10909-007-9544-1

Vancouver

Todoshchenko IA, Alles H, Junes HJ, Manninen MS, Parshin AY, Tsepelin V. Elementary excitations in solid and liquid He-4 at the melting pressure. Journal of Low Temperature Physics. 2008 Feb;150(3-4):258-266. doi: 10.1007/s10909-007-9544-1

Author

Todoshchenko, I. A. ; Alles, H. ; Junes, H. J. et al. / Elementary excitations in solid and liquid He-4 at the melting pressure. In: Journal of Low Temperature Physics. 2008 ; Vol. 150, No. 3-4. pp. 258-266.

Bibtex

@article{46f00aa7fb4f40b9b7120f1ba9b63713,
title = "Elementary excitations in solid and liquid He-4 at the melting pressure.",
abstract = "Recent discovery of a nonclassical rotational inertia (NCRI) in solid He-4 below 0.2 K by Kim and Chan has revived great interest in the problem of supersolidity and initiated intensive study on the properties of solid He-4. A direct proof that the onset of NCRI corresponds to the supersolid transition would be the observation of a corresponding drop of the entropy of solid He-4 below the transition temperature. We have measured the melting pressure of ultrapure He-4 in the temperature range from 0.01 to 0.45 K with several single crystals grown at different pressures and with the accuracy of 0.5 mu bar. In addition, supplementary measurements of the pressure in liquid He-4 at constant volume have been performed, which allowed us to eliminate the contribution of the temperature-dependent properties of the pressure gauge from the measured melting pressure data. With the correction to the temperature-dependent sensitivity of the pressure gauge, the variation of the melting pressure of He-4 below 320 mK obeys the pure T-4 law due to phonons with the accuracy of 0.5 mu bar, and no sign of the transition is seen (Todoshchenko et al. in JETP Lett. 85:454, 2007). This sets the upper limit of similar to 5 center dot 10(-8) R for a possible excess entropy in high-quality He-4 crystals below 320 mK. At higher temperatures the contribution from rotons in the superfluid He-4 has been observed. The thermal expansion coefficient of the superfluid He-4 has been measured in the range from 0.01 to 0.7 K with the accuracy of similar to 10(-7) 1/K, or by two orders of magnitude better than in previous measurements. The roton contributions to the melting pressure and to the pressure in liquid at a constant volume are consistent and yield the value of 6.8 K for the roton gap, which is very close to the values obtained with other methods. As no contribution due to weakly interacting vacancies to the melting pressure of He-4 has been observed, the lower limit of about 5.5 K for their activation energy can be set.",
keywords = "quantum solids, supersolids, excitations in quantum systems, HE-4, HELIUM, CRYSTALS",
author = "Todoshchenko, {I. A.} and H. Alles and Junes, {H. J.} and Manninen, {M. S.} and Parshin, {A. Y.} and Victor Tsepelin",
year = "2008",
month = feb,
doi = "10.1007/s10909-007-9544-1",
language = "English",
volume = "150",
pages = "258--266",
journal = "Journal of Low Temperature Physics",
issn = "0022-2291",
publisher = "SPRINGER/PLENUM PUBLISHERS",
number = "3-4",

}

RIS

TY - JOUR

T1 - Elementary excitations in solid and liquid He-4 at the melting pressure.

AU - Todoshchenko, I. A.

AU - Alles, H.

AU - Junes, H. J.

AU - Manninen, M. S.

AU - Parshin, A. Y.

AU - Tsepelin, Victor

PY - 2008/2

Y1 - 2008/2

N2 - Recent discovery of a nonclassical rotational inertia (NCRI) in solid He-4 below 0.2 K by Kim and Chan has revived great interest in the problem of supersolidity and initiated intensive study on the properties of solid He-4. A direct proof that the onset of NCRI corresponds to the supersolid transition would be the observation of a corresponding drop of the entropy of solid He-4 below the transition temperature. We have measured the melting pressure of ultrapure He-4 in the temperature range from 0.01 to 0.45 K with several single crystals grown at different pressures and with the accuracy of 0.5 mu bar. In addition, supplementary measurements of the pressure in liquid He-4 at constant volume have been performed, which allowed us to eliminate the contribution of the temperature-dependent properties of the pressure gauge from the measured melting pressure data. With the correction to the temperature-dependent sensitivity of the pressure gauge, the variation of the melting pressure of He-4 below 320 mK obeys the pure T-4 law due to phonons with the accuracy of 0.5 mu bar, and no sign of the transition is seen (Todoshchenko et al. in JETP Lett. 85:454, 2007). This sets the upper limit of similar to 5 center dot 10(-8) R for a possible excess entropy in high-quality He-4 crystals below 320 mK. At higher temperatures the contribution from rotons in the superfluid He-4 has been observed. The thermal expansion coefficient of the superfluid He-4 has been measured in the range from 0.01 to 0.7 K with the accuracy of similar to 10(-7) 1/K, or by two orders of magnitude better than in previous measurements. The roton contributions to the melting pressure and to the pressure in liquid at a constant volume are consistent and yield the value of 6.8 K for the roton gap, which is very close to the values obtained with other methods. As no contribution due to weakly interacting vacancies to the melting pressure of He-4 has been observed, the lower limit of about 5.5 K for their activation energy can be set.

AB - Recent discovery of a nonclassical rotational inertia (NCRI) in solid He-4 below 0.2 K by Kim and Chan has revived great interest in the problem of supersolidity and initiated intensive study on the properties of solid He-4. A direct proof that the onset of NCRI corresponds to the supersolid transition would be the observation of a corresponding drop of the entropy of solid He-4 below the transition temperature. We have measured the melting pressure of ultrapure He-4 in the temperature range from 0.01 to 0.45 K with several single crystals grown at different pressures and with the accuracy of 0.5 mu bar. In addition, supplementary measurements of the pressure in liquid He-4 at constant volume have been performed, which allowed us to eliminate the contribution of the temperature-dependent properties of the pressure gauge from the measured melting pressure data. With the correction to the temperature-dependent sensitivity of the pressure gauge, the variation of the melting pressure of He-4 below 320 mK obeys the pure T-4 law due to phonons with the accuracy of 0.5 mu bar, and no sign of the transition is seen (Todoshchenko et al. in JETP Lett. 85:454, 2007). This sets the upper limit of similar to 5 center dot 10(-8) R for a possible excess entropy in high-quality He-4 crystals below 320 mK. At higher temperatures the contribution from rotons in the superfluid He-4 has been observed. The thermal expansion coefficient of the superfluid He-4 has been measured in the range from 0.01 to 0.7 K with the accuracy of similar to 10(-7) 1/K, or by two orders of magnitude better than in previous measurements. The roton contributions to the melting pressure and to the pressure in liquid at a constant volume are consistent and yield the value of 6.8 K for the roton gap, which is very close to the values obtained with other methods. As no contribution due to weakly interacting vacancies to the melting pressure of He-4 has been observed, the lower limit of about 5.5 K for their activation energy can be set.

KW - quantum solids

KW - supersolids

KW - excitations in quantum systems

KW - HE-4

KW - HELIUM

KW - CRYSTALS

UR - http://www.scopus.com/inward/record.url?scp=38549106630&partnerID=8YFLogxK

U2 - 10.1007/s10909-007-9544-1

DO - 10.1007/s10909-007-9544-1

M3 - Journal article

VL - 150

SP - 258

EP - 266

JO - Journal of Low Temperature Physics

JF - Journal of Low Temperature Physics

SN - 0022-2291

IS - 3-4

ER -