We have studied the effect of uniaxial stress ${\mathrm{\sigma }}_{11}$ along the a direction, up to 150 MPa, on the thermoelectric power S(${\mathrm{\sigma }}_{11}$,T) and electrical resistance R(${\mathrm{\sigma }}_{11}$,T) of (Bi,Pb${)}_2$${\mathrm{Sr}}_2$${\mathrm{Ca}}_2$${\mathrm{Cu}}_3$${\mathrm{O}}_{\mathit{x}}$ single crystals from the transition temperature to room temperature. Both S and R increase monotonically with increasing ${\mathrm{\sigma }}_{11}$. Above ${\mathit{T}}_{\mathit{c}}$, S(${\mathrm{\sigma }}_{11}$,T) is positive and linear with T, and ΔS(${\mathrm{\sigma }}_{11}$,T)/ΔT=-41 nV/${\mathrm{K}}^2$ for all ${\mathrm{\sigma }}_{11}$. The extrapolated S(${\mathrm{\sigma }}_{11}$,T=0) increases with ${\mathrm{\sigma }}_{11}$, with ΔS(${\mathrm{\sigma }}_{11}$,0)/Δ${\mathrm{\sigma }}_{11}$=(1.5±0.4)μV ${\mathrm{K}}^{\mathrm{-}1}$ ${\mathrm{GPa}}^{\mathrm{-}1}$. The effect of ${\mathrm{\sigma }}_{11}$ on S(${\mathrm{\sigma }}_{11}$,0) is similar to the effect of a reduction in the hole density due to annealing under different oxygen atmospheres. S(${\mathrm{\sigma }}_{11}$,T) drops sharply at the superconducting transition temperature ${\mathit{T}}_{\mathit{c}}$(${\mathrm{\sigma }}_{11}$). We discuss our results in terms of several recently proposed models.

• Received 7 July 1993

DOI:https://doi.org/10.1103/PhysRevB.48.13141