Superconductivity in A15 compounds under nonhydrostatic stress

Abstract

The effect of nonhydrostatic stress on the superconducting transition temperature Tc of the A15 compounds has been studied theoretically. We have assumed that the superconductivity pertains to the narrow band that evolves from the doubly degenerate Γ12 state near the Fermi energy. Apart from explaining the existing experimental results, this analysis shows that the reduction of Tc should depend only on (σ12+σ22)1/2, where σ1=(s1-s2)/ √2 , σ2=(2s3-s1 -s2)/ √6 , and si are the stress components in the Voigt notation. It has also been argued that, for a given strain, the fractional reduction of Tc should be inversely proportional to the residual resistivity when the crystal disorder is small. Experimental verification of these results should throw light on the electronic band structure, the origin of the high Tc, and the effect of crystal disorder in these compounds.

Source-reported materials — not catalogue approval

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