Effect of large uniaxial stress on the superconducting transition temperature of zinc and cadmium

"Whiskers" of Zn and Cd can support large elastic stress ({~} 8 kbar). We have measured the change in the superconducting transition temperature Tc with stress σ in these whiskers. In Cd we find (∂Tc∂σ)_σ=0 to be 3.7 ×{} 10^-10 K m²/N for stress parallel to the hexagonal axis, and -0.46 ×{} 10^-10 K m²/N for stress perpendicular to the hexagonal axis. For Zn, (∂Tc∂σ_∥)_σ=0 was measured to be 5.1 ×{} 10^-10 K m²/N and (∂Tc∂σ_⊥)_σ=0 was -1.0 ×{} 10^-10 K m²/N. An anomalous relation between Tc and σ was found in Cd and is attributed to changes in Fermi-surface topology at high stress. As in other materials the large anisotropy in ∂Tc∂σ in Cd and Zn can be explained by anisotropies in the stress dependence of the lattice and electronic properties.