Anisotropy of the electrical conductivity in the one-dimensional conductor K2[Pt(CN)4]Br0·30.3(H2O)
1974; Elsevier BV; Volume: 35; Issue: 1 Linguagem: Inglês
10.1016/0022-3697(74)90014-6
ISSN1879-2553
Autores Tópico(s)Solid-state spectroscopy and crystallography
ResumoUsing a method developed by Montgomery we have measured simultaneously σ| and σ⊥ the conductivities parallel and perpendicular to the c-axis respectively in single crystals of K2[Pt(CN)4]Br0·30.3(H2O). The anisotropy σ|σ⊥ is of the order of 105 at room temperature but decreases to 3.103 at 35°K. None of the hitherto proposed models allows a detailed comparison between predicted and measured anisotropy. However, the experimental results seem to contradict the two dimensional variable range hopping model. The Bloch, Weisman and Varma model predicts an infinite anisotropy and thus can not be compared with experiment. Recent diffuse X-ray scattering and NMR experiments suggest that the material becomes a band semi-conductor at low temperatures due to a Peierls instability. This model is consistent with our results. While defects and random potentials do not seem to play the dominant rôle assumed in earlier models, they may determine the longitudinal mobility of the excited carriers and hence the anisotropy.
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