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We report a study of the effect of uniaxial stress on the electrical properties of T12Mo6Se6. Stress suppresses the superconducting transition temperature and induces a metal-to-nonmetal phase transition. Nonlinear I-V characteristics and broadband noise measurements in the semiconducting phase suggest that the transition may be due to the formation of a charge-density or spin-density wave. A transition temperature T~= 15+3 K and energy gap Eg =57 K are deduced from resistance measurements in the nonmetallic state.

We have measured the nonlinear conductivity, the thermopower, and the narrow-band noise in TaS3 as a function of elastic strain e along the chain axis. Both the thermopower and the chargedensity-wave (CDW) conductivity are dependent on the temperature and c. history of the sample. There are indications that the CDW becomes commensurate at @=0. 5%, where (at most temperatures) (1) there is a maximum in the threshold field for nonlinear conductivity, (2) there are anomalies in the thermopower and resistance, and (3) the narrow-band noise disappears.

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The electrical resistance of Bi and Bi-6 at.% Sb whiskers has been measured. Sample diameters were as low as 140 nm, lengths as large as 1.5 mm, and residual resistances as high as 165 k£2. Down to temperatures of 0.4 K, metallic behavior persists; the resistance R decreases with decreasing temperature T in contrast to other systems in which electron localization is invoked to explain negative dR/dT's.