Tensor Magnetothermal Resistance in YBa 2 Cu 3 O 7</mml:…
1995; American Physical Society; Volume: 74; Issue: 25 Linguagem: Inglês
10.1103/physrevlett.74.5136
ISSN1092-0145
AutoresFang Yu, M. B. Salamon, A. J. Leggett, W. C. Lee, D. M. Ginsberg,
Tópico(s)Quantum and electron transport phenomena
ResumoA magnetic field in the $a\ensuremath{-}b$ plane of an untwinned single crystal of ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}x}$ $({T}_{c}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}92\mathrm{K})$ is found to induce field-dependent off-diagonal elements in the thermal conductivity tensor at 10 K. The principal axes of the field-dependent part of the tensor lie along equivalent $〈110〉$ directions; a principal component is maximized when the field is along the corresponding principal axis. A model that considers Andreev reflection of thermally excited quasiparticles by vortex screening currents gives semiquantitative agreement with experiment only if the gap function has nodes in the vicinity of $〈110〉$.
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