ISSN:
1573-7357
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract We report on thermal conductivity measurements of the quasi-onedimensional single crystals (Ta 1−x Nb x Se 4 ) 2 I (x = 0, 0.008, 0.01) between 50 mK and 6 K. The thermal conductivity of a (TaSe 4 ) 2 I sample obeys a cubic variation below 0.8 K, in good agreement with the boundary scattering regime. For two Nb doped samples, the thermal conductivity between 0.1 K and 1 K obeys a quasiquadratic regime, which is ascribed to extended “linear or planar defects,” specific to this one-dimensional structure, and introduced either by doping or by successive thermal cycling, while it obeys a cubic variation below 0.1 K, as in the case of pure (TaSe 4 ) 2 I. In the vicinity of 1 K and 2 K for pure and 1 at. % Nb doped samples, thermal conductivity shows a very sharp peak, which exceeds the low-temperature cubic boundary Casimir regime, or the quasi quadratic regime, respectively. The presence of the peak in these systems is explained by a phonon Poiseuille flow, originating from their strong anharmonicity, amplified by the lattice anisotropy.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1022273107580
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