J. Phys. I France 5 (1995) 437-442
Quantum Transport in the Charge-Density-Wave State of the Quasi Two-Dimensional Bronzes ( ) ( )C. Le Touze1, G. Bonfait2, C. Schlenker1, J. Dumas1, M. Almeida2, M. Greenblatt3 and Z.S. Teweldemedhin3
1 Laboratoire d'Etudes des Propriétés Electroniques des Solides CNRS, BP 166, 38042 Grenoble Cedex 9, France
2 Departamento de Quimica, ICEN, INETI, P-2686 Sacavem Codex, Portugal
3 Department of Chemistry, Rutgers, The State University of New Jersey, Piscataway, N.J. 08855-0939, U.S.A.
(Received 6 February 1995, accepted 17 February 1995)
Magnetotransport has been studied on the quasi two-dimensional monophosphate tungsten bronzes (PO 2) 4(WO 3) 2m for m=4 and 6, between 0.3 and 300 K in fields up to 18 T. These compounds show several charge density wave transitions. Large magnetoresistance is found in the charge-density-wave state for magnetic fields applied perpendicular to the layers. At low temperatures, Shubnikov-de Haas oscillations are attributed to the existence of small carrier pockets left by the charge density wave gap opening. The size of these pockets is of the order of a few % of the two-dimensional high temperature Brillouin zone and smaller in the case m=6 than in m=4. This is due to a more pronounced low-dimensional character and therefore to a better Fermi surface nesting in the compound m=6 than in m=4.
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