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VOLUME 92 (2010) | ISSUE 8 |
PAGE 585
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Second wind of the Dulong-Petit Law at a quantum critical point
V. A. Khodel, J. W. Clark, V. R. Shaginyan*/, M. V. Zverev+°
+Russian Research Center Kurchatov Institute, 123182 Moscow, Russia McDonnell Center for the Space Sciences & Department of Physics, Washington University, St. Louis, MO 63130, USA *Petersburg Nuclear Physics Institute RAS, 188300 Gatchina, Russia °Moscow Institute of Rhysics and Technology, 123098 Moscow, Russia
Abstract
Renewed interest in 3He physics has been stimulated by
experimental observation of non-Fermi-liquid behavior of dense
3He films at low temperatures. Abnormal behavior of the specific
heat C(T) of two-dimensional liquid 3He is demonstrated in the
occurrence of a T-independent β term in C(T). To uncover
the origin of this phenomenon, we have considered the group
velocity of transverse zero sound propagating in a strongly
correlated Fermi liquid. For the first time, it is shown that if
two-dimensional liquid 3He is located in the vicinity of the
quantum critical point associated with a divergent quasiparticle
effective mass, the group velocity depends strongly on temperature
and vanishes as T is lowered toward zero. The predicted vigorous
dependence of the group velocity can be detected in experimental
measurements on liquid 3He films. We have demonstrated that the
contribution to the specific heat coming from the boson part of the
free energy due to the transverse zero-sound mode follows the
Dulong-Petit Law. In the case of two-dimensional liquid 3He, the
specific heat becomes independent of temperature at some
characteristic temperature of a few mK.
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