J. Phys. I France
Volume 5, Numéro 2, February 1995
Page(s) 221 - 233
DOI: 10.1051/jp1:1995124
J. Phys. I France 5 (1995) 221-233

Electron Tunneling Studies in the Charge Density Wave State of the Quasi Bidimensional Metal $\eta$-Mo 4O 11

J.P. Sorbier1, H. Tortel1, C. Schlenker2 and H. Guyot2

1  Laboratoire d'Electronique des Milieux Condensés, Université de Provence, Centre de St Jérôme, 13397 Marseille Cedex 20, France
2  Laboratoire d'Etudes des Propriétés Electroniques des Solides, CNRS, B.P. 166, 38042 Grenoble Cedex 9, France

(Received 30 May 1994, accepted in final form 27 October 1994)

Electron tunneling studies have been performed on junctions made with the quasi bidimensional oxide $\eta$-Mo 4O 11 and a lead film sepearted by an insulating oxide layer. The density of states in the vicinity of the Fermi level has been obtained along two directions (parallel and perpendicular to the layers) in the temperature range 1 K-90 K. The data from the differential conductance as a function of dc bias voltage are consistent with gap openings taking place at $T_{\rm p1}=100$ K and $T_{\rm p2}= 30$ K. Both electron instabilities are attributed to charge density waves and the anisotropy of the density of states is related to the anisotropy of the Fermi surface. For tunneling current in the plane of the layers, weak oscillations are found in the density of states at low temperatures. They are possibly due to the existence of several types of small electron and hole pockets induced on the Fermi surface by the charge density wave gap openings.

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