Effect of uniaxial stress on the transport properties ofTaSe3

We have measured the effect of elastic, uniaxial stress on the resistance R, the thermoelectric power (TEP), and the superconducting transition temperature $T_c$ of ${\mathrm{TaSe}}_3$. We find that there is a nearly discontinuous change in R and in the TEP at a stress σ of about 1.2 GPa at 20 K. In this change R increases by several orders of magnitude, while the TEP changes sign and increases by several orders of magnitude. At higher temperatures this change becomes less pronounced and occurs over a larger range of σ. We suggest that this change is due to a Fermi-surface topology change, a structural phase transition, or a charge-density-wave transition. We found no evidence for a metal-to-nonmetal transition just above the normal-superconducting transition at $T_c$.