J. Phys. I France
Volume 6, Number 12, December 1996
Page(s) 2141 - 2149
DOI: 10.1051/jp1:1996210
J. Phys. I France 6 (1996) 2141-2149

Charge Density Wave Dynamics in Quasi-One Dimensional Molecular Conductors: a Comparative Study of (Per) $\mathsf{_2}$M(mnt) $\mathsf{_2}$ with M = Au, Pt

E.B. Lopes1, M.J. Matos2, R.T. Henriques3, M. Almeida1 and J. Dumas4

1  Departamento de Química, Instituto Tecnológico e Nuclear, 2686 Sacavém Codex, Portugal
2  Instituto Superior de Engenharia de Lisboa, 1900 Lisbon, Portugal
3  Departamento Engenharia Química, Instituto Superior Técnico, 1096 Lisbon Codex, Portugal
4  Laboratoire d'Études des Propriétés Électroniques des Solides, CNRS, BP 166, 38042 Grenoble Cedex 9, France

(Received 14 May 1996, revised 22 July 1996, accepted 20 August 1996)

The molecular compounds (Per) 2M(mnt) 2 where Per = perylene and mnt = maleonitriledithiolate are quasi-one dimensional conductors which undergo metal-to-semiconductor transitions towards a commensurate charge density wave (CDW) state, at $T_{\rm c} = 8$ K for M = Pt and $T_{\rm c}=12$ K for M = Au. above a threshold field, these molecular systems show nonlinear transport due to CDW motion as it is well demonstrated in the case of the Pt compound, where the Fourier analysis of the voltage at constant current clearly reveals one fundamental frequency proportional to the excess CDW current and several harmonics. A comparative study by pulsed current methods of the transient CDW dynamics is reported for these compounds, showing different threshold fields and variable degrees of CDW screening by the normal carriers. The temperature dependence of the threshold fields for both compounds is compared. The results are discussed in relation with current models for CDW transport.

© Les Editions de Physique 1996